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141-443: Meat is animal tissue , often muscle , that is eaten as food. Humans have hunted and farmed other animals for meat since prehistory. The Neolithic Revolution allowed the domestication of vertebrates , including chickens , sheep , goats , pigs , horses , and cattle , starting around 11,000 years ago. Since then, selective breeding has enabled farmers to produce meat with the qualities desired by producers and consumers. Meat

282-630: A genetically modified organism in the process. However, some broad definitions of genetic engineering include selective breeding . Cloning and stem cell research, although not considered genetic engineering, are closely related and genetic engineering can be used within them. Synthetic biology is an emerging discipline that takes genetic engineering a step further by introducing artificially synthesised material into an organism. Plants, animals or microorganisms that have been changed through genetic engineering are termed genetically modified organisms or GMOs. If genetic material from another species

423-484: A promoter and terminator region, which initiate and end transcription . A selectable marker gene is added, which in most cases confers antibiotic resistance , so researchers can easily determine which cells have been successfully transformed. The gene can also be modified at this stage for better expression or effectiveness. These manipulations are carried out using recombinant DNA techniques, such as restriction digests , ligations and molecular cloning. There are

564-425: A biotech company, Advanced Genetic Sciences (AGS) applied for U.S. government authorisation to perform field tests with the ice-minus strain of Pseudomonas syringae to protect crops from frost, but environmental groups and protestors delayed the field tests for four years with legal challenges. In 1987, the ice-minus strain of P. syringae became the first genetically modified organism (GMO) to be released into

705-656: A broad one. Static magnetic fields , for reasons still unknown, retard animal development. The quality and quantity of usable meat depends on the animal's plane of nutrition , i.e., whether it is over- or underfed. Scientists disagree about how exactly the plane of nutrition influences carcase composition. The composition of the diet, especially the amount of protein provided, is an important factor regulating animal growth. Ruminants , which may digest cellulose , are better adapted to poor-quality diets, but their ruminal microorganisms degrade high-quality protein if supplied in excess. Because producing high-quality protein animal feed

846-743: A function is called cellular differentiation . Cells of meristematic tissue differentiate to form different types of permanent tissues. There are 2 types of permanent tissues: Simple permanent tissue is a group of cells which are similar in origin, structure, and function. They are of three types: Parenchyma (Greek, para – 'beside'; enchyma– infusion – 'tissue') is the bulk of a substance. In plants, it consists of relatively unspecialized living cells with thin cell walls that are usually loosely packed so that intercellular spaces are found between cells of this tissue. These are generally isodiametric, in shape. They contain small number of vacuoles or sometimes they even may not contain any vacuole. Even if they do so

987-604: A function of providing mechanical support. They do not have inter-cellular spaces between them. Lignin deposition is so thick that the cell walls become stronger, rigid and impermeable to water, which are also known as a stone cells or sclereids. These tissues are mainly of two types: sclerenchyma fiber and sclereids. Sclerenchyma fiber cells have a narrow lumen and are long, narrow and unicellular. Fibers are elongated cells that are strong and flexible, often used in ropes. Sclereids have extremely thick cell walls and are brittle, and are found in nutshells and legumes. The entire surface of

1128-542: A gene coding for a useful protein, such as an enzyme, so that they will overexpress the desired protein. Mass quantities of the protein can then be manufactured by growing the transformed organism in bioreactor equipment using industrial fermentation , and then purifying the protein. Some genes do not work well in bacteria, so yeast, insect cells or mammalian cells can also be used. These techniques are used to produce medicines such as insulin , human growth hormone , and vaccines , supplements such as tryptophan , aid in

1269-456: A gene is isolated it can be stored inside the bacteria providing an unlimited supply for research. Organisms are genetically engineered to discover the functions of certain genes. This could be the effect on the phenotype of the organism, where the gene is expressed or what other genes it interacts with. These experiments generally involve loss of function, gain of function, tracking and expression. Organisms can have their cells transformed with

1410-598: A genetically modified virus has been used in a research laboratory as a scaffold for assembling a more environmentally friendly lithium-ion battery . Bacteria have also been engineered to function as sensors by expressing a fluorescent protein under certain environmental conditions. One of the best-known and controversial applications of genetic engineering is the creation and use of genetically modified crops or genetically modified livestock to produce genetically modified food . Crops have been developed to increase production, increase tolerance to abiotic stresses , alter

1551-464: A number of techniques used to insert genetic material into the host genome. Some bacteria can naturally take up foreign DNA . This ability can be induced in other bacteria via stress (e.g. thermal or electric shock), which increases the cell membrane's permeability to DNA; up-taken DNA can either integrate with the genome or exist as extrachromosomal DNA . DNA is generally inserted into animal cells using microinjection , where it can be injected through

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1692-583: A predetermined age or weight, livestock are usually transported en masse to the slaughterhouse. Depending on its length and circumstances, this may exert stress and injuries on the animals, and some may die en route . Unnecessary stress in transport may adversely affect the quality of the meat. In particular, the muscles of stressed animals are low in water and glycogen , and their pH fails to attain acidic values, all of which results in poor meat quality. Animals are usually slaughtered by being first stunned and then exsanguinated (bled out). Death results from

1833-893: A result of cobalt deficiency in the soil. Plant toxins are a risk to grazing animals; for instance, sodium fluoroacetate , found in some African and Australian plants, kills by disrupting the cellular metabolism . Some man-made pollutants such as methylmercury and some pesticide residues present a particular hazard as they bioaccumulate in meat, potentially poisoning consumers. Practices such as confinement in factory farming have generated concerns for animal welfare . Animals have abnormal behaviors such as tail-biting, cannibalism, and feather pecking . Invasive procedures such as beak trimming , castration , and ear notching have similarly been questioned. Breeding for high productivity may affect welfare, as when broiler chickens are bred to be very large and to grow rapidly. Broilers often have leg deformities and become lame, and many die from

1974-535: A supporting tissue in stems of young plants. It provides mechanical support, elasticity, and tensile strength to the plant body. It helps in manufacturing sugar and storing it as starch. It is present in the margin of leaves and resists tearing effect of the wind. Sclerenchyma (Greek, Sclerous means hard and enchyma means infusion) consists of thick-walled, dead cells and protoplasm is negligible. These cells have hard and extremely thick secondary walls due to uniform distribution and high secretion of lignin and have

2115-536: A thin and elastic primary cell wall made of cellulose . They are compactly arranged without inter-cellular spaces between them. Each cell contains a dense cytoplasm and a prominent cell nucleus . The dense protoplasm of meristematic cells contains very few vacuoles . Normally the meristematic cells are oval, polygonal , or rectangular in shape. Meristematic tissue cells have a large nucleus with small or no vacuoles because they have no need to store anything, as opposed to their function of multiplying and increasing

2256-413: A virus was used to insert a healthy gene into the skin cells of a boy suffering from a rare skin disease, epidermolysis bullosa , in order to grow, and then graft healthy skin onto 80 percent of the boy's body which was affected by the illness. Germline gene therapy would result in any change being inheritable, which has raised concerns within the scientific community. In 2015, CRISPR was used to edit

2397-589: A wide range of plants, animals and microorganisms. Bacteria , the first organisms to be genetically modified, can have plasmid DNA inserted containing new genes that code for medicines or enzymes that process food and other substrates . Plants have been modified for insect protection, herbicide resistance , virus resistance, enhanced nutrition, tolerance to environmental pressures and the production of edible vaccines . Most commercialised GMOs are insect resistant or herbicide tolerant crop plants. Genetically modified animals have been used for research, model animals and

2538-594: A wide range of stretch lengths. It is found in such organs as sea anemone tentacles and the body wall of sea cucumbers . Skeletal muscle contracts rapidly but has a limited range of extension. It is found in the movement of appendages and jaws. Obliquely striated muscle is intermediate between the other two. The filaments are staggered and this is the type of muscle found in earthworms that can extend slowly or make rapid contractions. In higher animals striated muscles occur in bundles attached to bone to provide movement and are often arranged in antagonistic sets. Smooth muscle

2679-515: A year later the company produced a human protein ( somatostatin ) in E. coli . Genentech announced the production of genetically engineered human insulin in 1978. In 1980, the U.S. Supreme Court in the Diamond v. Chakrabarty case ruled that genetically altered life could be patented. The insulin produced by bacteria was approved for release by the Food and Drug Administration (FDA) in 1982. In 1983,

2820-513: Is a central element in human anatomy , and he considered organs as collections of often disparate tissues, rather than as entities in themselves". Although he worked without a microscope , Bichat distinguished 21 types of elementary tissues from which the organs of the human body are composed, a number later reduced by other authors. Genetic engineering This is an accepted version of this page Genetic engineering , also called genetic modification or genetic manipulation ,

2961-466: Is a living tissue of primary body like Parenchyma . Cells are thin-walled but possess thickening of cellulose , water and pectin substances ( pectocellulose ) at the corners where a number of cells join. This tissue gives tensile strength to the plant and the cells are compactly arranged and have very little inter-cellular spaces. It occurs chiefly in hypodermis of stems and leaves. It is absent in monocots and in roots. Collenchymatous tissue acts as

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3102-489: Is a risk; in 2013, products in Europe labelled as beef actually contained horse meat . Meat can be cooked in many ways, including braising , broiling , frying , grilling , and roasting . Meat can be cured by smoking , which preserves and flavors food by exposing it to smoke from burning or smoldering wood. Other methods of curing include pickling , salting , and air-drying. Some recipes call for raw meat; steak tartare

3243-441: Is added to the host, the resulting organism is called transgenic . If genetic material from the same species or a species that can naturally breed with the host is used the resulting organism is called cisgenic . If genetic engineering is used to remove genetic material from the target organism the resulting organism is termed a knockout organism. In Europe genetic modification is synonymous with genetic engineering while within

3384-405: Is also known as conducting and vascular tissue. The common types of complex permanent tissue are: Xylem and phloem together form vascular bundles. Xylem (Greek, xylos = wood) serves as a chief conducting tissue of vascular plants. It is responsible for the conduction of water and inorganic solutes. Xylem consists of four kinds of cells: Xylem tissue is organised in a tube-like fashion along

3525-696: Is an equally important plant tissue as it also is part of the 'plumbing system' of a plant. Primarily, phloem carries dissolved food substances throughout the plant. This conduction system is composed of sieve-tube member and companion cells, that are without secondary walls. The parent cells of the vascular cambium produce both xylem and phloem. This usually also includes fibers, parenchyma and ray cells. Sieve tubes are formed from sieve-tube members laid end to end. The end walls, unlike vessel members in xylem, do not have openings. The end walls, however, are full of small pores where cytoplasm extends from cell to cell. These porous connections are called sieve plates. In spite of

3666-486: Is an important tool for natural scientists , with the creation of transgenic organisms one of the most important tools for analysis of gene function. Genes and other genetic information from a wide range of organisms can be inserted into bacteria for storage and modification, creating genetically modified bacteria in the process. Bacteria are cheap, easy to grow, clonal , multiply quickly, relatively easy to transform and can be stored at -80 °C almost indefinitely. Once

3807-403: Is anticipated. Heat regulation in livestock is of economic significance, as mammals attempt to maintain a constant optimal body temperature. Low temperatures tend to prolong animal development and high temperatures tend to delay it. Depending on their size, body shape and insulation through tissue and fur, some animals have a relatively narrow zone of temperature tolerance and others (e.g. cattle)

3948-415: Is being reversed by consumer demand for leaner meat. The fatty deposits near the muscle fibers in meats soften meat when it is cooked, improve its flavor, and make the meat seem juicier. Fat around meat further contains cholesterol . The increase in meat consumption after 1960 is associated with significant imbalances of fat and cholesterol in the human diet. Biomass of mammals on Earth Upon reaching

4089-508: Is called an extracellular matrix . This matrix can be liquid or rigid. For example, blood contains plasma as its matrix and bone's matrix is rigid. Connective tissue gives shape to organs and holds them in place. Blood, bone, tendon, ligament, adipose, and areolar tissues are examples of connective tissues. One method of classifying connective tissues is to divide them into three types: fibrous connective tissue, skeletal connective tissue, and fluid connective tissue. Muscle cells (myocytes) form

4230-400: Is considered as the "Father of Histology". Plant histology is studied in both plant anatomy and physiology . The classical tools for studying tissues are the paraffin block in which tissue is embedded and then sectioned, the histological stain , and the optical microscope . Developments in electron microscopy , immunofluorescence , and the use of frozen tissue-sections have enhanced

4371-407: Is consumed, and egg and/or dairy consumption may or may not be strictly restricted. The type of meat consumed varies between different cultures. The amount and kind of meat consumed varies by income, both between countries and within a given country. Horses are commonly eaten in countries such as France, Italy, Germany and Japan. Horses and other large mammals such as reindeer were hunted during

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4512-444: Is expensive, several techniques are employed or experimented with to ensure maximum utilization of protein. These include the treatment of feed with formalin to protect amino acids during their passage through the rumen , the recycling of manure by feeding it back to cattle mixed with feed concentrates, or the conversion of petroleum hydrocarbons to protein through microbial action. In plant feed, environmental factors influence

4653-411: Is found in the walls of the uterus , bladder , intestines , stomach , oesophagus , respiratory airways , and blood vessels . Cardiac muscle is found only in the heart , allowing it to contract and pump blood through the body. Cells comprising the central nervous system and peripheral nervous system are classified as nervous (or neural) tissue. In the central nervous system, neural tissues form

4794-408: Is generated through genetic engineering is considered to be genetically modified (GM) and the resulting entity is a genetically modified organism (GMO). The first GMO was a bacterium generated by Herbert Boyer and Stanley Cohen in 1973. Rudolf Jaenisch created the first GM animal when he inserted foreign DNA into a mouse in 1974. The first company to focus on genetic engineering, Genentech ,

4935-557: Is important to economies and cultures around the world. The word meat comes from the Old English word mete , meaning food in general. In modern usage, meat primarily means skeletal muscle with its associated fat and connective tissue, but it can include offal , other edible organs such as liver and kidney . The term is sometimes used in a more restrictive sense to mean the flesh of mammalian species (pigs, cattle, sheep, goats, etc.) raised and prepared for human consumption, to

5076-871: Is made from minced raw beef. Pâtés are made with ground meat and fat, often including liver . Meat, in particular red and processed meat, is linked to a variety of health risks. The 2015–2020 Dietary Guidelines for Americans asked men and teenage boys to increase their consumption of vegetables or other underconsumed foods (fruits, whole grains, and dairy) while reducing intake of protein foods (meats, poultry, and eggs) that they currently overconsume. Toxic compounds including heavy metals , mycotoxins , pesticide residues, dioxins , polychlorinated biphenyl can contaminate meat. Processed, smoked and cooked meat may contain carcinogens such as polycyclic aromatic hydrocarbons . Toxins may be introduced to meat as part of animal feed, as veterinary drug residues, or during processing and cooking. Such compounds are often metabolized in

5217-509: Is mainly composed of water, protein, and fat. Its quality is affected by many factors, including the genetics, health, and nutritional status of the animal involved. Without preservation, bacteria and fungi decompose and spoil unprocessed meat within hours or days. Under optimal conditions, meat is edible raw , but is often normally eaten cooked—such as by stewing or roasting —or processed —such as by smoking or salting . The consumption of meat (especially red and processed meat) increases

5358-422: Is not necessary. Selectable markers are used to easily differentiate transformed from untransformed cells. These markers are usually present in the transgenic organism, although a number of strategies have been developed that can remove the selectable marker from the mature transgenic plant. Further testing using PCR, Southern hybridization , and DNA sequencing is conducted to confirm that an organism contains

5499-493: Is particularly prevalent in the US, but has been banned in the EU, partly because it causes antimicrobial resistance in pathogenic microorganisms. The biochemical composition of meat varies in complex ways depending on the species, breed, sex, age, plane of nutrition, training and exercise of the animal, as well as on the anatomical location of the musculature involved. Even between animals of

5640-704: Is possible to create animal model organisms of human diseases. As well as producing hormones, vaccines and other drugs, genetic engineering has the potential to cure genetic diseases through gene therapy . Chinese hamster ovary (CHO) cells are used in industrial genetic engineering. Additionally mRNA vaccines are made through genetic engineering to treat viruses such as COVID-19 . The same techniques that are used to produce drugs can also have industrial applications such as producing enzymes for laundry detergent, cheeses and other products. The rise of commercialised genetically modified crops has provided economic benefit to farmers in many different countries, but has also been

5781-563: Is separated by using restriction enzymes to cut the DNA into fragments or polymerase chain reaction (PCR) to amplify up the gene segment. These segments can then be extracted through gel electrophoresis . If the chosen gene or the donor organism's genome has been well studied it may already be accessible from a genetic library . If the DNA sequence is known, but no copies of the gene are available, it can also be artificially synthesised . Once isolated

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5922-477: Is somewhat variable. Most classification schemes combine a description of the cell-shape in the upper layer of the epithelium with a word denoting the number of layers: either simple (one layer of cells) or stratified (multiple layers of cells). However, other cellular features such as cilia may also be described in the classification system. Some common kinds of epithelium are listed below: Connective tissues are made up of cells separated by non-living material, which

6063-418: Is tender and pliable when cooked just after death or after the resolution of rigor , but tough when cooked during rigor. As the muscle pigment myoglobin denatures, its iron oxidizes , which may cause a brown discoloration near the surface of the meat. Ongoing proteolysis contributes to conditioning: hypoxanthine , a breakdown product of ATP, contributes to meat's flavor and odor, as do other products of

6204-401: Is the genetic engineering of humans , generally by replacing defective genes with effective ones. Clinical research using somatic gene therapy has been conducted with several diseases, including X-linked SCID , chronic lymphocytic leukemia (CLL), and Parkinson's disease . In 2012, Alipogene tiparvovec became the first gene therapy treatment to be approved for clinical use. In 2015

6345-422: Is the modification and manipulation of an organism's genes using technology . It is a set of technologies used to change the genetic makeup of cells, including the transfer of genes within and across species boundaries to produce improved or novel organisms . New DNA is obtained by either isolating and copying the genetic material of interest using recombinant DNA methods or by artificially synthesising

6486-449: Is very low in carbohydrates and does not contain dietary fiber. The fat content of meat varies widely with the species and breed of animal, the way in which the animal was raised, what it was fed, the part of the body, and the methods of butchering and cooking. Wild animals such as deer are leaner than farm animals, leading those concerned about fat content to choose game such as venison . Decades of breeding meat animals for fatness

6627-515: The American Association for the Advancement of Science say that absent scientific evidence of harm even voluntary labeling is misleading and will falsely alarm consumers. Labeling of GMO products in the marketplace is required in 64 countries. Labeling can be mandatory up to a threshold GM content level (which varies between countries) or voluntary. In Canada and the US labeling of GM food

6768-507: The CRISPR/Cas9 system, a technique which can be used to easily and specifically alter the genome of almost any organism. Creating a GMO is a multi-step process. Genetic engineers must first choose what gene they wish to insert into the organism. This is driven by what the aim is for the resultant organism and is built on earlier research. Genetic screens can be carried out to determine potential genes and further tests then used to identify

6909-778: The Translational Genomics Research Institute showed that nearly half (47%) of the meat and poultry in U.S. grocery stores were contaminated with S. aureus , with more than half (52%) of those bacteria resistant to antibiotics. A 2018 investigation by the Bureau of Investigative Journalism and The Guardian found that around 15 percent of the US population suffers from foodborne illnesses every year. The investigation highlighted unsanitary conditions in US-based meat plants, which included meat products covered in excrement and abscesses "filled with pus". Complete cooking and

7050-431: The brain and spinal cord . In the peripheral nervous system, neural tissues form the cranial nerves and spinal nerves , inclusive of the motor neurons . Mineralized tissues are biological tissues that incorporate minerals into soft matrices. Such tissues may be found in both plants and animals. Xavier Bichat introduced the word tissue into the study of anatomy by 1801. He was "the first to propose that tissue

7191-463: The ectoderm and endoderm (or their precursor in sponges ), with a small contribution from the mesoderm , forming the endothelium , a specialized type of epithelium that composes the vasculature . By contrast, a true epithelial tissue is present only in a single layer of cells held together via occluding junctions called tight junctions , to create a selectively permeable barrier. This tissue covers all organismal surfaces that come in contact with

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7332-579: The host organism or into a cell that is then fused or hybridised with the host. This relies on recombinant nucleic acid techniques to form new combinations of heritable genetic material followed by the incorporation of that material either indirectly through a vector system or directly through micro-injection , macro-injection or micro-encapsulation . Genetic engineering does not normally include traditional breeding, in vitro fertilisation , induction of polyploidy , mutagenesis and cell fusion techniques that do not use recombinant nucleic acids or

7473-434: The infectious sequences . Genetic engineering is also used to create animal models of human diseases. Genetically modified mice are the most common genetically engineered animal model. They have been used to study and model cancer (the oncomouse ), obesity, heart disease, diabetes, arthritis, substance abuse, anxiety, aging and Parkinson disease. Potential cures can be tested against these mouse models. Gene therapy

7614-573: The postwar period , governments gave farmers guaranteed prices to increase animal production. The effect was to raise output at the cost of increased inputs such as of animal feed and veterinary medicines, as well as of animal disease and environmental pollution. In 1966, the United States, the United Kingdom and other industrialized nations, began factory farming of beef and dairy cattle and domestic pigs. Intensive animal farming became globalized in

7755-501: The DNA of non-viable human embryos , leading scientists of major world academies to call for a moratorium on inheritable human genome edits. There are also concerns that the technology could be used not just for treatment, but for enhancement, modification or alteration of a human beings' appearance, adaptability, intelligence, character or behavior. The distinction between cure and enhancement can also be difficult to establish. In November 2018, He Jiankui announced that he had edited

7896-432: The DNA. A construct is usually created and used to insert this DNA into the host organism. The first recombinant DNA molecule was made by Paul Berg in 1972 by combining DNA from the monkey virus SV40 with the lambda virus . As well as inserting genes , the process can be used to remove, or " knock out ", genes. The new DNA can be inserted randomly, or targeted to a specific part of the genome . An organism that

8037-449: The FDA approved a drug produced in goat milk. Genetic engineering has potential applications in conservation and natural area management. Gene transfer through viral vectors has been proposed as a means of controlling invasive species as well as vaccinating threatened fauna from disease. Transgenic trees have been suggested as a way to confer resistance to pathogens in wild populations. With

8178-904: The National Cancer Institute published results of a study which found that human subjects who ate beef rare or medium-rare had less than one third the risk of stomach cancer than those who ate beef medium-well or well-done. While eating muscle meat raw may be the only way to avoid HCAs fully, the National Cancer Institute states that cooking meat below 100 °C (212 °F) creates "negligible amounts" of HCAs. Microwaving meat before cooking may reduce HCAs by 90%. Nitrosamines , present in processed and cooked foods, are carcinogenic, being linked to colon cancer. Polycyclic aromatic hydrocarbons , present in processed, smoked and cooked foods, are similarly carcinogenic. Bacterial contamination has been seen with meat products. A 2011 study by

8319-613: The USDA, FDA and EPA. The Cartagena Protocol on Biosafety , an international treaty that governs the transfer, handling, and use of GMOs, was adopted on 29 January 2000. One hundred and fifty-seven countries are members of the Protocol, and many use it as a reference point for their own regulations. The legal and regulatory status of GM foods varies by country, with some nations banning or restricting them, and others permitting them with widely differing degrees of regulation. Some countries allow

8460-523: The United States and Europe . Genetic engineering : Process of inserting new genetic information into existing cells in order to modify a specific organism for the purpose of changing its characteristics. Note : Adapted from ref. Genetic engineering is a process that alters the genetic structure of an organism by either removing or introducing DNA , or modifying existing genetic material in situ. Unlike traditional animal and plant breeding , which involves doing multiple crosses and then selecting for

8601-478: The United States of America and Canada genetic modification can also be used to refer to more conventional breeding methods. Humans have altered the genomes of species for thousands of years through selective breeding , or artificial selection as contrasted with natural selection . More recently, mutation breeding has used exposure to chemicals or radiation to produce a high frequency of random mutations, for selective breeding purposes. Genetic engineering as

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8742-404: The United States. One of the key issues concerning regulators is whether GM products should be labeled. The European Commission says that mandatory labeling and traceability are needed to allow for informed choice, avoid potential false advertising and facilitate the withdrawal of products if adverse effects on health or the environment are discovered. The American Medical Association and

8883-420: The active contractile tissue of the body. Muscle tissue functions to produce force and cause motion, either locomotion or movement within internal organs. Muscle is formed of contractile filaments and is separated into three main types; smooth muscle , skeletal muscle and cardiac muscle . Smooth muscle has no striations when examined microscopically. It contracts slowly but maintains contractibility over

9024-543: The animal genome . To enable such manipulation, the genomes of many animals are being mapped . Some research has already seen commercial application. For instance, a recombinant bacterium has been developed which improves the digestion of grass in the rumen of cattle, and some specific features of muscle fibers have been genetically altered. Experimental reproductive cloning of commercially important meat animals such as sheep, pig or cattle has been successful. Multiple asexual reproduction of animals bearing desirable traits

9165-659: The animal to store energy and consisting of "true fats" ( esters of glycerol with fatty acids ), or intramuscular fat, which contains phospholipids and cholesterol . Meat can be broadly classified as "red" or "white" depending on the concentration of myoglobin in muscle fiber. When myoglobin is exposed to oxygen , reddish oxymyoglobin develops, making myoglobin-rich meat appear red. The redness of meat depends on species, animal age, and fiber type: Red meat contains more narrow muscle fibers that tend to operate over long periods without rest, while white meat contains more broad fibers that tend to work in short fast bursts, such as

9306-411: The animal's commercial value. Genetic analysis continues to reveal the genetic mechanisms that control numerous aspects of the endocrine system and, through it, meat growth and quality. Genetic engineering techniques can shorten breeding programs significantly because they allow for the identification and isolation of genes coding for desired traits, and for the reincorporation of these genes into

9447-514: The approaches taken by governments to assess and manage the risks associated with the development and release of GMOs. The development of a regulatory framework began in 1975, at Asilomar , California. The Asilomar meeting recommended a set of voluntary guidelines regarding the use of recombinant technology. As the technology improved the US established a committee at the Office of Science and Technology , which assigned regulatory approval of GM food to

9588-466: The availability of crucial nutrients or micronutrients , a lack or excess of which can cause a great many ailments. In Australia, where the soil contains limited phosphate , cattle are fed additional phosphate to increase the efficiency of beef production. Also in Australia, cattle and sheep in certain areas were often found losing their appetite and dying in the midst of rich pasture; this was found to be

9729-473: The best candidates. The development of microarrays , transcriptomics and genome sequencing has made it much easier to find suitable genes. Luck also plays its part; the Roundup Ready gene was discovered after scientists noticed a bacterium thriving in the presence of the herbicide. The next step is to isolate the candidate gene. The cell containing the gene is opened and the DNA is purified. The gene

9870-434: The best possible genetic quality, and the efficiency of this method is improved through the administration of hormones that synchronize the ovulation cycles within groups of females. Growth hormones , particularly anabolic agents such as steroids , are used in some countries to accelerate muscle growth in animals. This practice has given rise to the beef hormone controversy , an international trade dispute. It may decrease

10011-539: The body to form harmful by-products. Negative effects depend on the individual genome, diet, and history of the consumer. The consumption of processed and red meat carries an increased risk of cancer. The International Agency for Research on Cancer (IARC), a specialized agency of the World Health Organization (WHO), classified processed meat (e.g., bacon, ham, hot dogs, sausages) as, "carcinogenic to humans (Group 1), based on sufficient evidence in humans that

10152-476: The brief flight of the chicken. The meat of adult mammals such as cows , sheep , and horses is considered red, while chicken and turkey breast meat is considered white. Muscle tissue is high in protein, containing all of the essential amino acids , and in most cases is a good source of zinc , vitamin B 12 , selenium , phosphorus , niacin , vitamin B 6 , choline , riboflavin and iron. Several forms of meat are high in vitamin K . Muscle tissue

10293-403: The carcass is necessary because blood causes the meat to have an unappealing appearance and is a breeding ground for microorganisms. After exsanguination, the carcass is dressed; that is, the head, feet, hide (except hogs and some veal), excess fat, viscera and offal are removed, leaving only bones and edible muscle. Cattle and pig carcases, but not those of sheep, are then split in half along

10434-529: The careful avoidance of recontamination reduce the risk of bacterial infections from meat. Tissue (biology) Biological organisms follow this hierarchy : Cells < Tissue < Organ < Organ System < Organism The English word "tissue" derives from the French word " tissu ", the past participle of the verb tisser, "to weave". The study of tissues is known as histology or, in connection with disease, as histopathology . Xavier Bichat

10575-408: The cell membrane permeable to plasmid DNA. As only a single cell is transformed with genetic material, the organism must be regenerated from that single cell. In plants this is accomplished through the use of tissue culture . In animals it is necessary to ensure that the inserted DNA is present in the embryonic stem cells . Bacteria consist of a single cell and reproduce clonally so regeneration

10716-763: The cell's nuclear envelope directly into the nucleus , or through the use of viral vectors . Plant genomes can be engineered by physical methods or by use of Agrobacterium for the delivery of sequences hosted in T-DNA binary vectors . In plants the DNA is often inserted using Agrobacterium -mediated transformation , taking advantage of the Agrobacterium s T-DNA sequence that allows natural insertion of genetic material into plant cells. Other methods include biolistics , where particles of gold or tungsten are coated with DNA and then shot into young plant cells, and electroporation , which involves using an electric shock to make

10857-456: The colourless substance that covers the sieve plate. Callose stays in solution as long as the cell contents are under pressure. Phloem transports food and materials in plants upwards and downwards as required. Animal tissues are grouped into four basic types: connective , muscle , nervous , and epithelial . Collections of tissues joined in units to serve a common function compose organs. While most animals can generally be considered to contain

10998-443: The composition of the food, or to produce novel products. The first crops to be released commercially on a large scale provided protection from insect pests or tolerance to herbicides . Fungal and virus resistant crops have also been developed or are in development. This makes the insect and weed management of crops easier and can indirectly increase crop yield. GM crops that directly improve yield by accelerating growth or making

11139-604: The concept of substantial equivalence . The European Union by contrast has possibly the most stringent GMO regulations in the world. All GMOs, along with irradiated food , are considered "new food" and subject to extensive, case-by-case, science-based food evaluation by the European Food Safety Authority . The criteria for authorisation fall in four broad categories: "safety", "freedom of choice", "labelling", and "traceability". The level of regulation in other countries that cultivate GMOs lie in between Europe and

11280-1122: The consumption of processed meat causes colorectal cancer." IARC classified red meat as "probably carcinogenic to humans (Group 2A), based on limited evidence that the consumption of red meat causes cancer in humans and strong mechanistic evidence supporting a carcinogenic effect." Cancer Research UK , National Health Service (NHS) and the National Cancer Institute have stated that red and processed meat intake increases risk of bowel cancer . The American Cancer Society in their "Diet and Physical Activity Guideline", stated "evidence that red and processed meats increase cancer risk has existed for decades, and many health organizations recommend limiting or avoiding these foods." The Canadian Cancer Society have stated that "eating red and processed meat increases cancer risk". A 2021 review found an increase of 11–51% risk of multiple cancer per 100g/d increment of red meat, and an increase of 8–72% risk of multiple cancer per 50g/d increment of processed meat. Cooking muscle meat creates heterocyclic amines (HCAs), which are thought to increase cancer risk in humans. Researchers at

11421-568: The decomposition of muscle fat and protein. When meat is industrially processed, additives are used to protect or modify its flavor or color, to improve its tenderness, juiciness or cohesiveness, or to aid with its preservation . A bioarchaeological (specifically, isotopic analysis ) study of early medieval England found, based on the funerary record, that high-meat protein diets were extremely rare, and that (contrary to previously held assumptions) elites did not consume more meat than non-elites, and men did not consume more meat than women. In

11562-413: The defective gene with a functioning one. It is an important tool in research that allows the function of specific genes to be studied. Drugs, vaccines and other products have been harvested from organisms engineered to produce them. Crops have been developed that aid food security by increasing yield, nutritional value and tolerance to environmental stresses. The DNA can be introduced directly into

11703-484: The demands of customers. The trend towards selling meat in pre-packaged cuts has increased the demand for larger breeds of cattle, better suited to producing such cuts. Animals not previously exploited for their meat are now being farmed, including mammals such as antelope , zebra, water buffalo and camel, as well as non-mammals, such as crocodile, emu and ostrich. Organic farming supports an increasing demand for meat produced to that standard. Several factors affect

11844-531: The detail that can be observed in tissues. With these tools, the classical appearances of tissues can be examined in health and disease , enabling considerable refinement of medical diagnosis and prognosis . In plant anatomy , tissues are categorized broadly into three tissue systems: the epidermis , the ground tissue , and the vascular tissue . Plant tissues can also be divided differently into two types: Meristematic tissue consists of actively dividing cells and leads to increase in length and thickness of

11985-567: The direct manipulation of DNA by humans outside breeding and mutations has only existed since the 1970s. The term "genetic engineering" was coined by the Russian-born geneticist Nikolay Timofeev-Ressovsky in his 1934 paper "The Experimental Production of Mutations", published in the British journal Biological Reviews. Jack Williamson used the term in his science fiction novel Dragon's Island, published in 1951 – one year before DNA's role in heredity

12126-573: The earliest uses of genetic engineering was to mass-produce human insulin in bacteria. This application has now been applied to human growth hormones , follicle stimulating hormones (for treating infertility), human albumin , monoclonal antibodies , antihemophilic factors , vaccines and many other drugs. Mouse hybridomas , cells fused together to create monoclonal antibodies , have been adapted through genetic engineering to create human monoclonal antibodies. Genetically engineered viruses are being developed that can still confer immunity, but lack

12267-433: The ends. They do not have end openings such as the vessels. The end overlap with each other, with pairs of pits present. The pit pairs allow water to pass from cell to cell. Though most conduction in xylem tissue is vertical, lateral conduction along the diameter of a stem is facilitated via rays. Rays are horizontal rows of long-living parenchyma cells that arise out of the vascular cambium. Phloem consists of: Phloem

12408-555: The environment when a strawberry field and a potato field in California were sprayed with it. Both test fields were attacked by activist groups the night before the tests occurred: "The world's first trial site attracted the world's first field trasher". The first field trials of genetically engineered plants occurred in France and the US in 1986, tobacco plants were engineered to be resistant to herbicides . The People's Republic of China

12549-507: The exclusion of fish , other seafood, insects , poultry, or other animals. Paleontological evidence suggests that meat constituted a substantial proportion of the diet of the earliest humans. Early hunter-gatherers depended on the organized hunting of large animals such as bison and deer . Animals were domesticated in the Neolithic , enabling the systematic production of meat and the breeding of animals to improve meat production. In

12690-414: The external environment such as the skin , the airways, and the digestive tract. It serves functions of protection, secretion , and absorption, and is separated from other tissues below by a basal lamina . The connective tissue and the muscular are derived from the mesoderm. The nervous tissue is derived from the ectoderm. The epithelial tissues are formed by cells that cover the organ surfaces, such as

12831-399: The fact that their cytoplasm is actively involved in the conduction of food materials, sieve-tube members do not have nuclei at maturity. It is the companion cells that are nestled between sieve-tube members that function in some manner bringing about the conduction of food. Sieve-tube members that are alive contain a polymer called callose, a carbohydrate polymer, forming the callus pad/callus,

12972-471: The first synthetic genome and inserted it into an empty bacterial cell. The resulting bacterium, named Mycoplasma laboratorium , could replicate and produce proteins. Four years later this was taken a step further when a bacterium was developed that replicated a plasmid containing a unique base pair , creating the first organism engineered to use an expanded genetic alphabet. In 2012, Jennifer Doudna and Emmanuelle Charpentier collaborated to develop

13113-583: The first GMO designed as a pet, was sold in the United States in December 2003. In 2016 salmon modified with a growth hormone were sold. Genetic engineering has been applied in numerous fields including research, medicine, industrial biotechnology and agriculture. In research, GMOs are used to study gene function and expression through loss of function, gain of function, tracking and expression experiments. By knocking out genes responsible for certain conditions it

13254-443: The first day after death, glycolysis continues until the accumulation of lactic acid causes the pH to reach about 5.5. The remaining glycogen , about 18 g per kg, increases the water-holding capacity and tenderness of cooked meat. Rigor mortis sets in a few hours after death as adenosine triphosphate is used up. This causes the muscle proteins actin and myosin to combine into rigid actomyosin . This in turn lowers

13395-482: The food supply and intellectual property rights have also been raised as potential issues. These concerns have led to the development of a regulatory framework, which started in 1975. It has led to an international treaty, the Cartagena Protocol on Biosafety , that was adopted in 2000. Individual countries have developed their own regulatory systems regarding GMOs, with the most marked differences occurring between

13536-400: The four tissue types, the manifestation of these tissues can differ depending on the type of organism. For example, the origin of the cells comprising a particular tissue type may differ developmentally for different classifications of animals. Tissue appeared for the first time in the diploblasts , but modern forms only appeared in triploblasts . The epithelium in all animals is derived from

13677-464: The gene is ligated into a plasmid that is then inserted into a bacterium. The plasmid is replicated when the bacteria divide, ensuring unlimited copies of the gene are available. The RK2 plasmid is notable for its ability to replicate in a wide variety of single-celled organisms , which makes it suitable as a genetic engineering tool. Before the gene is inserted into the target organism it must be combined with other genetic elements. These include

13818-404: The genome of pigs to induce the growth of human organs, with the aim of increasing the success of pig to human organ transplantation . Scientists are creating "gene drives", changing the genomes of mosquitoes to make them immune to malaria, and then looking to spread the genetically altered mosquitoes throughout the mosquito population in the hopes of eliminating the disease. Genetic engineering

13959-458: The genome, and use the cell's endogenous mechanisms to repair the induced break by the natural processes of homologous recombination and nonhomologous end-joining . There are four families of engineered nucleases: meganucleases , zinc finger nucleases , transcription activator-like effector nucleases (TALENs), and the Cas9-guideRNA system (adapted from CRISPR ). TALEN and CRISPR are

14100-466: The genomes of two human embryos, to attempt to disable the CCR5 gene, which codes for a receptor that HIV uses to enter cells. The work was widely condemned as unethical, dangerous, and premature. Currently, germline modification is banned in 40 countries. Scientists that do this type of research will often let embryos grow for a few days without allowing it to develop into a baby. Researchers are altering

14241-400: The girth and length of the plant, with no intercellular spaces. Permanent tissues may be defined as a group of living or dead cells formed by meristematic tissue and have lost their ability to divide and have permanently placed at fixed positions in the plant body. Meristematic tissues that take up a specific role lose the ability to divide. This process of taking up a permanent shape, size and

14382-453: The glycolytic enzymes – are involved in glycolysis , the conversion of sugars into high-energy molecules, especially adenosine triphosphate (ATP). The two most abundant myofibrillar proteins, myosin and actin , form the muscle's overall structure and enable it to deliver power, consuming ATP in the process. The remaining protein mass includes connective tissue ( collagen and elastin ). Fat in meat can be either adipose tissue , used by

14523-449: The growth and development of meat. Some economically important traits in meat animals are heritable to some degree, and can thus be selected for by animal breeding . In cattle, certain growth features are controlled by recessive genes which have not so far been controlled, complicating breeding. One such trait is dwarfism ; another is the doppelender or " double muscling " condition, which causes muscle hypertrophy and thereby increases

14664-511: The host genome or targeted to a specific location. The technique of gene targeting uses homologous recombination to make desired changes to a specific endogenous gene. This tends to occur at a relatively low frequency in plants and animals and generally requires the use of selectable markers . The frequency of gene targeting can be greatly enhanced through genome editing . Genome editing uses artificially engineered nucleases that create specific double-stranded breaks at desired locations in

14805-454: The import of GM food with authorisation, but either do not allow its cultivation (Russia, Norway, Israel) or have provisions for cultivation even though no GM products are yet produced (Japan, South Korea). Most countries that do not allow GMO cultivation do permit research. Some of the most marked differences occur between the US and Europe. The US policy focuses on the product (not the process), only looks at verifiable scientific risks and uses

14946-532: The increase. Overall, diets that include meat are the most common worldwide according to the results of a 2018 Ipsos MORI study of 16–64 years olds in 28 countries. Ipsos states "An omnivorous diet is the most common diet globally, with non-meat diets (which can include fish) followed by over a tenth of the global population." Approximately 87% of people include meat in their diet in some frequency. 73% of meat eaters included it in their diet regularly and 14% consumed meat only occasionally or infrequently. Estimates of

15087-678: The increasing risks of maladaptation in organisms as a result of climate change and other perturbations, facilitated adaptation through gene tweaking could be one solution to reducing extinction risks. Applications of genetic engineering in conservation are thus far mostly theoretical and have yet to be put into practice. Genetic engineering is also being used to create microbial art . Some bacteria have been genetically engineered to create black and white photographs. Novelty items such as lavender-colored carnations , blue roses , and glowing fish , have also been produced through genetic engineering. The regulation of genetic engineering concerns

15228-660: The late Paleolithic in western Europe. Dogs are consumed in China, South Korea and Vietnam. Dogs are occasionally eaten in the Arctic regions. Historically, dog meat has been consumed in various parts of the world, such as Hawaii, Japan, Switzerland and Mexico. Cats are sometimes eaten, such as in Peru. Guinea pigs are raised for their flesh in the Andes . Whales and dolphins are hunted, partly for their flesh, in several countries. Misidentification

15369-404: The later years of the 20th century, replacing traditional stock rearing in countries around the world. In 1990 intensive animal farming accounted for 30% of world meat production and by 2005, this had risen to 40%. Modern agriculture employs techniques such as progeny testing to speed selective breeding , allowing the rapid acquisition of the qualities desired by meat producers. For instance, in

15510-471: The main axes of stems and roots. It consists of a combination of parenchyma cells, fibers, vessels, tracheids, and ray cells. Longer tubes made up of individual cellssels tracheids, while vessel members are open at each end. Internally, there may be bars of wall material extending across the open space. These cells are joined end to end to form long tubes. Vessel members and tracheids are dead at maturity. Tracheids have thick secondary cell walls and are tapered at

15651-402: The meat industry than in any other British business" except finance. The US was a meat importing country by 1926. Truncated lifespan as a result of intensive breeding allows more meat to be produced from fewer animals. The world cattle population was about 600 million in 1929, with 700 million sheep and goats and 300 million pigs. According to the Food and Agriculture Organization ,

15792-415: The meat's water-holding capacity, so the meat loses water or "weeps". In muscles that enter rigor in a contracted position, actin and myosin filaments overlap and cross-bond, resulting in meat that becomes tough when cooked. Over time, muscle proteins denature in varying degree, with the exception of the collagen and elastin of connective tissue , and rigor mortis resolves. These changes mean that meat

15933-423: The mid ventral axis, and the carcase is cut into wholesale pieces. The dressing and cutting sequence, long a province of manual labor, is being progressively automated. Under hygienic conditions and without other treatment, meat can be stored at above its freezing point (−1.5 °C) for about six weeks without spoilage, during which time it undergoes an aging process that increases its tenderness and flavor. During

16074-434: The monkey virus SV40 with that of the lambda virus . In 1973 Herbert Boyer and Stanley Cohen created the first transgenic organism by inserting antibiotic resistance genes into the plasmid of an Escherichia coli bacterium. A year later Rudolf Jaenisch created a transgenic mouse by introducing foreign DNA into its embryo, making it the world's first transgenic animal These achievements led to concerns in

16215-498: The new gene. These tests can also confirm the chromosomal location and copy number of the inserted gene. The presence of the gene does not guarantee it will be expressed at appropriate levels in the target tissue so methods that look for and measure the gene products (RNA and protein) are also used. These include northern hybridisation , quantitative RT-PCR , Western blot , immunofluorescence , ELISA and phenotypic analysis. The new genetic material can be inserted randomly within

16356-514: The nineteenth century, meat consumption in Britain was the highest in Europe, exceeded only by that in British colonies. In the 1830s consumption per head in Britain was about 34 kilograms (75 lb) a year, rising to 59 kilograms (130 lb) in 1912. In 1904, laborers consumed 39 kilograms (87 lb) a year while aristocrats ate 140 kilograms (300 lb). There were some 43,000 butcher's shops in Britain in 1910, with "possibly more money invested in

16497-431: The non-meat diets were analysed. About 3% of people followed vegan diets, where consumption of meat, eggs, and dairy are abstained from. About 5% of people followed vegetarian diets, where consumption of meat is abstained from, but egg and/or dairy consumption is not strictly restricted. About 3% of people followed pescetarian diets, where consumption of the meat of land animals is abstained from, fish meat and other seafood

16638-432: The one or the other procedure, depending on the methods employed. Stunning can be effected through asphyxiating the animals with carbon dioxide , shooting them with a gun or a captive bolt pistol , or shocking them with electric current. The exsanguination is accomplished by severing the carotid artery and the jugular vein in cattle and sheep, and the anterior vena cava in pigs. Draining as much blood as possible from

16779-399: The organism with the desired phenotype , genetic engineering takes the gene directly from one organism and delivers it to the other. This is much faster, can be used to insert any genes from any organism (even ones from different domains ) and prevents other undesirable genes from also being added. Genetic engineering could potentially fix severe genetic disorders in humans by replacing

16920-458: The overall consumption for white meat has increased from the 20th to the 21st centuries. Poultry meat has increased by 76.6% per kilo per capita and pig meat by 19.7%. Bovine meat has decreased from 10.4 kg (22 lb 15 oz) per capita in 1990 to 9.6 kg (21 lb 3 oz) per capita in 2009. FAO analysis found that 357 million tonnes of meat were produced in 2021, 53% more than in 2000, with chicken meat representing more than half

17061-411: The plant consists of a single layer of cells called epidermis or surface tissue. The entire surface of the plant has this outer layer of the epidermis. Hence it is also called surface tissue. Most of the epidermal cells are relatively flat. The outer and lateral walls of the cell are often thicker than the inner walls. The cells form a continuous sheet without intercellular spaces. It protects all parts of

17202-564: The plant more hardy (by improving salt, cold or drought tolerance) are also under development. In 2016 Salmon have been genetically modified with growth hormones to reach normal adult size much faster. GMOs have been developed that modify the quality of produce by increasing the nutritional value or providing more industrially useful qualities or quantities. The Amflora potato produces a more industrially useful blend of starches. Soybeans and canola have been genetically modified to produce more healthy oils. The first commercialised GM food

17343-464: The plant. The outer epidermis is coated with a waxy thick layer called cutin which prevents loss of water. The epidermis also consists of stomata (singular:stoma) which helps in transpiration . The complex permanent tissue consists of more than one type of cells having a common origin which work together as a unit. Complex tissues are mainly concerned with the transportation of mineral nutrients, organic solutes (food materials), and water. That's why it

17484-689: The plant. The primary growth of a plant occurs only in certain specific regions, such as in the tips of stems or roots. It is in these regions that meristematic tissue is present. Cells of this type of tissue are roughly spherical or polyhedral to rectangular in shape, with thin cell walls . New cells produced by meristem are initially those of meristem itself, but as the new cells grow and mature, their characteristics slowly change and they become differentiated as components of meristematic tissue, being classified as: There are two types of meristematic Tissue 1.Primary meristem. 2.Secondary meristem. The cells of meristematic tissue are similar in structure and have

17625-430: The production of agricultural or pharmaceutical products. The genetically modified animals include animals with genes knocked out , increased susceptibility to disease , hormones for extra growth and the ability to express proteins in their milk. Genetic engineering has many applications to medicine that include the manufacturing of drugs, creation of model animals that mimic human conditions and gene therapy . One of

17766-570: The production of food ( chymosin in cheese making) and fuels. Other applications with genetically engineered bacteria could involve making them perform tasks outside their natural cycle, such as making biofuels , cleaning up oil spills, carbon and other toxic waste and detecting arsenic in drinking water. Certain genetically modified microbes can also be used in biomining and bioremediation , due to their ability to extract heavy metals from their environment and incorporate them into compounds that are more easily recoverable. In materials science ,

17907-446: The risk of certain negative health outcomes including cancer, coronary heart disease , and diabetes . Meat production is a major contributor to environmental issues including global warming , pollution, and biodiversity loss , at every scale from local to global. Some people choose not to eat meat ( vegetarians and vegans ) for reasons such as ethics , environmental effects, health concerns, or religious dietary rules. However, meat

18048-668: The same litter and sex there are considerable differences in such parameters as the percentage of intramuscular fat. Adult mammalian muscle consists of roughly 75 percent water, 19 percent protein, 2.5 percent intramuscular fat, 1.2 percent carbohydrates and 2.3 percent other soluble substances. These include organic compounds, especially amino acids , and inorganic substances such as minerals. Muscle proteins are either soluble in water ( sarcoplasmic proteins, about 11.5 percent of total muscle mass) or in concentrated salt solutions ( myofibrillar proteins, about 5.5 percent of mass). There are several hundred sarcoplasmic proteins. Most of them –

18189-491: The scientific community about potential risks from genetic engineering, which were first discussed in depth at the Asilomar Conference in 1975. One of the main recommendations from this meeting was that government oversight of recombinant DNA research should be established until the technology was deemed safe. In 1976 Genentech, the first genetic engineering company, was founded by Herbert Boyer and Robert Swanson and

18330-434: The source of most of the controversy surrounding the technology. This has been present since its early use; the first field trials were destroyed by anti-GM activists. Although there is a scientific consensus that currently available food derived from GM crops poses no greater risk to human health than conventional food, critics consider GM food safety a leading concern. Gene flow , impact on non-target organisms, control of

18471-423: The stress of handling and transport. Meat producers may seek to improve the fertility of female animals through the administration of gonadotrophic or ovulation -inducing hormones . In pig production, sow infertility is a common problem – possibly due to excessive fatness. No methods currently exist to augment the fertility of male animals. Artificial insemination is now routinely used to produce animals of

18612-639: The surface of skin , the airways , surfaces of soft organs, the reproductive tract , and the inner lining of the digestive tract . The cells comprising an epithelial layer are linked via semi-permeable, tight junctions ; hence, this tissue provides a barrier between the external environment and the organ it covers. In addition to this protective function, epithelial tissue may also be specialized to function in secretion , excretion and absorption . Epithelial tissue helps to protect organs from microorganisms, injury, and fluid loss. Functions of epithelial tissue: There are many kinds of epithelium, and nomenclature

18753-511: The tenderness of meat, although research on this is inconclusive, and have other effects on the composition of the muscle flesh. Where castration is used to improve control over male animals, its side effects can be counteracted by the administration of hormones. Myostatin has been used to produce muscle hypertrophy . Sedatives may be administered to animals to counteract stress factors and increase weight gain. The feeding of antibiotics to certain animals increases growth rates. This practice

18894-412: The two most commonly used and each has its own advantages. TALENs have greater target specificity, while CRISPR is easier to design and more efficient. In addition to enhancing gene targeting, engineered nucleases can be used to introduce mutations at endogenous genes that generate a gene knockout . Genetic engineering has applications in medicine, research, industry and agriculture and can be used on

19035-654: The vacuole is of much smaller size than of normal animal cells. This tissue provides support to plants and also stores food. Chlorenchyma is a special type of parenchyma that contains chlorophyll and performs photosynthesis. In aquatic plants, aerenchyma tissues, or large air cavities, give support to float on water by making them buoyant. Parenchyma cells called idioblasts have metabolic waste. Spindle shaped fibers are also present in this cell to support them and known as prosenchyma, succulent parenchyma also noted. In xerophytes , parenchyma tissues store water. Collenchyma (Greek, 'Colla' means gum and 'enchyma' means infusion)

19176-443: The wake of well-publicized health concerns associated with saturated fats in the 1980s, the fat content of United Kingdom beef, pork and lamb fell from 20–26 percent to 4–8 percent within a few decades, due to both selective breeding for leanness and changed methods of butchery. Methods of genetic engineering that could improve the meat-producing qualities of animals are becoming available. Meat production continues to be shaped by

19317-490: Was a tomato that had delayed ripening, increasing its shelf life . Plants and animals have been engineered to produce materials they do not normally make. Pharming uses crops and animals as bioreactors to produce vaccines, drug intermediates, or the drugs themselves; the useful product is purified from the harvest and then used in the standard pharmaceutical production process. Cows and goats have been engineered to express drugs and other proteins in their milk, and in 2009

19458-494: Was approved safe by the Environmental Protection Agency , after having been approved by the FDA, making it the first pesticide producing crop to be approved in the US. In 2009 11 transgenic crops were grown commercially in 25 countries, the largest of which by area grown were the US, Brazil, Argentina, India, Canada, China, Paraguay and South Africa. In 2010, scientists at the J. Craig Venter Institute created

19599-477: Was confirmed by Alfred Hershey and Martha Chase , and two years before James Watson and Francis Crick showed that the DNA molecule has a double-helix structure – though the general concept of direct genetic manipulation was explored in rudimentary form in Stanley G. Weinbaum 's 1936 science fiction story Proteus Island . In 1972, Paul Berg created the first recombinant DNA molecules by combining DNA from

19740-495: Was founded in 1976 and started the production of human proteins. Genetically engineered human insulin was produced in 1978 and insulin-producing bacteria were commercialised in 1982. Genetically modified food has been sold since 1994, with the release of the Flavr Savr tomato. The Flavr Savr was engineered to have a longer shelf life, but most current GM crops are modified to increase resistance to insects and herbicides. GloFish ,

19881-527: Was the first country to commercialise transgenic plants, introducing a virus-resistant tobacco in 1992. In 1994 Calgene attained approval to commercially release the first genetically modified food , the Flavr Savr , a tomato engineered to have a longer shelf life. In 1994, the European Union approved tobacco engineered to be resistant to the herbicide bromoxynil , making it the first genetically engineered crop commercialised in Europe. In 1995, Bt potato

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