The Finnish Lapphund (or Finnish Lapponian Dog) ( Finnish : Suomenlapinkoira ) is a hardy, easy going, medium-size breed of Spitz type. Traditionally it has been used for herding reindeer . Although it is one of the most popular dog breeds in its native country, Finland , it is not very numerous outside of the Nordic countries .
116-537: The breed falls under the mitochondrial DNA sub- clade referred to as d1 that is only found in northern Scandinavia. It is the result of a female wolf-male dog hybridization that occurred post-domestication. Subclade d1 originated "at most 480–3,000 years ago" and is found in all Sami -related breeds: Finnish Lapphund, Swedish Lapphund , Lapponian Herder , Jamthund , Norwegian Elkhound and Hällefors Elkhound . The maternal wolf sequence that contributed to these breeds has not been matched across Eurasia and its branch on
232-505: A reduction of vision . Nuclear cataracts typically cause greater impairment of distance vision than of near vision. Those with posterior subcapsular cataracts usually complain of glare as their major symptom. The severity of cataract formation, assuming no other eye disease is present, is judged primarily by a visual acuity test. Other symptoms include frequent changes of glasses and colored halos due to hydration of lens. Congenital cataracts can result in amblyopia if not treated in
348-400: A vitrectomy —without ever having had cataract surgery—will experience progression of nuclear sclerosis after the operation. This may be because the native vitreous humor is different from the solutions used to replace the vitreous (vitreous substitutes), such as BSS Plus . This may also be because the native vitreous humour contains ascorbic acid which helps neutralize oxidative damage to
464-585: A database) to determine maternal lineage. Most often, the comparison is made with the revised Cambridge Reference Sequence . Vilà et al. have published studies tracing the matrilineal descent of domestic dogs from wolves. The concept of the Mitochondrial Eve is based on the same type of analysis, attempting to discover the origin of humanity by tracking the lineage back in time. Entities subject to uniparental inheritance and with little to no recombination may be expected to be subject to Muller's ratchet ,
580-680: A different classification and includes lamellar, polar, and sutural cataracts. Cataracts can be classified by using the lens opacities classification system LOCS III. In this system, cataracts are classified based on type as nuclear, cortical, or posterior. The cataracts are further classified based on severity on a scale from 1 to 5. The LOCS III system is highly reproducible. Risk factors such as UVB exposure and smoking can be addressed. Although no means of preventing cataracts has been scientifically proven, wearing sunglasses that block ultraviolet light may slow their development. While adequate intake of vitamins A , C , and E may protect against
696-500: A donor female, and nuclear DNA from the mother and father. In the spindle transfer procedure, the nucleus of an egg is inserted into the cytoplasm of an egg from a donor female which has had its nucleus removed, but still contains the donor female's mtDNA. The composite egg is then fertilized with the male's sperm. The procedure is used when a woman with genetically defective mitochondria wishes to procreate and produce offspring with healthy mitochondria. The first known child to be born as
812-435: A finding that has been rejected by other scientists. In sexual reproduction , mitochondria are normally inherited exclusively from the mother; the mitochondria in mammalian sperm are usually destroyed by the egg cell after fertilization. Also, mitochondria are present solely in the midpiece, which is used for propelling the sperm cells, and sometimes the midpiece, along with the tail, is lost during fertilization. In 1999 it
928-545: A healthy human sperm has been reported to contain on average 5 molecules), degradation of sperm mtDNA in the male genital tract and in the fertilized egg; and, at least in a few organisms, failure of sperm mtDNA to enter the egg. Whatever the mechanism, this single parent ( uniparental inheritance ) pattern of mtDNA inheritance is found in most animals, most plants and also in fungi. In a study published in 2018, human babies were reported to inherit mtDNA from both their fathers and their mothers resulting in mtDNA heteroplasmy ,
1044-485: A mane in most males. Although the coat is thick, it requires only a modest amount of maintenance. Weekly brushing is recommended throughout the year, except during shedding seasons, where a daily brush may be required. A wide variety of colours and markings are found in Finnish Lapphunds. Any colour is allowed in the breed standard, although a single colour should predominate. One of the most common colour combinations
1160-542: A mutation in mtDNA has been used to help diagnose prostate cancer in patients with negative prostate biopsy . mtDNA alterations can be detected in the bio-fluids of patients with cancer. mtDNA is characterized by the high rate of polymorphisms and mutations. Some of which are increasingly recognized as an important cause of human pathology such as oxidative phosphorylation (OXPHOS) disorders, maternally inherited diabetes and deafness (MIDD), Type 2 diabetes mellitus, Neurodegenerative disease , heart failure and cancer. Though
1276-626: A mutational (contrary to the selective one) explanation for the observation that long-lived species have GC-rich mtDNA: long-lived species become GC-rich simply because of their biased process of mutagenesis. An association between mtDNA mutational spectrum and species-specific life-history traits in mammals opens a possibility to link these factors together discovering new life-history-specific mutagens in different groups of organisms. Deletion breakpoints frequently occur within or near regions showing non-canonical (non-B) conformations, namely hairpins, cruciforms and cloverleaf-like elements. Moreover, there
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#17328759956241392-460: A needle-shaped instrument, Galen attempted to remove the cataract-affected lens of the eye. Muslim ophthalmologist Ammar Al-Mawsili , in his The Book of Choice in Ophthalmology , written circa 1000 CE, wrote of his invention of a syringe and the technique of cataract extraction while experimenting with it on a patient. In 1468 Abiathar Crescas , a Jewish physician and astrologer of
1508-521: A result of mitochondrial donation was a boy born to a Jordanian couple in Mexico on 6 April 2016. The concept that mtDNA is particularly susceptible to reactive oxygen species generated by the respiratory chain due to its proximity remains controversial. mtDNA does not accumulate any more oxidative base damage than nuclear DNA. It has been reported that at least some types of oxidative DNA damage are repaired more efficiently in mitochondria than they are in
1624-529: A ring of lighter-coloured hair around the eyes gives the impression that the dog is wearing spectacles. The spectacles of the Finnish Lapphund, while reminiscent of their cousins, the Keeshond , are larger and more pronounced. Like other spitz types, the tail is carried curving over the back. The Finnish Lapphund has a tail covered with thick, long hair. The tail may hang as the dog stands. The Finnish Lapphund
1740-507: A role in the mitochondrial bottleneck, exploiting cell-to-cell variability to ameliorate the inheritance of damaging mutations. According to Justin St. John and colleagues, "At the blastocyst stage, the onset of mtDNA replication is specific to the cells of the trophectoderm . In contrast, the cells of the inner cell mass restrict mtDNA replication until they receive the signals to differentiate to specific cell types." The two strands of
1856-435: A species and also for identifying and quantifying the phylogeny (evolutionary relationships; see phylogenetics ) among different species. To do this, biologists determine and then compare the mtDNA sequences from different individuals or species. Data from the comparisons is used to construct a network of relationships among the sequences, which provides an estimate of the relationships among the individuals or species from which
1972-623: A stabilisation or reduction in mutant load between generations. The mechanism underlying the bottleneck is debated, with a recent mathematical and experimental metastudy providing evidence for a combination of the random partitioning of mtDNAs at cell divisions and the random turnover of mtDNA molecules within the cell. Male mitochondrial DNA inheritance has been discovered in Plymouth Rock chickens . Evidence supports rare instances of male mitochondrial inheritance in some mammals as well. Specifically, documented occurrences exist for mice, where
2088-485: A therapeutic purpose. HBOT can have several side effects, including the long-term development of cataracts. This is rare and generally associated with multiple HBOT exposures over a long period. As it does not usually become symptomatic during HBOT, it may often go unrecognised and is probably under-reported. Evidence is emerging that lifetime dosage of oxygen may be a precipitating factor in the development of age-related cataracts. Nuclear cataracts have been hypothesized to be
2204-444: A timely manner. Age is the most common cause of cataracts. Lens proteins denature and degrade over time, and this process is accelerated by diseases such as diabetes mellitus and hypertension . Environmental factors, including toxins, radiation, and ultraviolet light have cumulative effects which are worsened by the loss of protective and restorative mechanisms due to alterations in gene expression and chemical processes within
2320-445: A trend to overuse cataract surgery has been noted, which may lead to disappointing results. Phacoemulsification is the most widely used cataract surgery in the developed world. This procedure uses ultrasonic energy to emulsify the cataract lens. Phacoemulsification typically comprises six steps: A Cochrane review found little to no difference in visual acuity as a function of the size of incisions made for phacoemulsification in
2436-442: Is 46 to 52 centimetres (18 to 20 in) at the withers for a male, and a slightly smaller 41 to 47 centimetres (16 to 19 in) for a female. However, some variation is allowed, since the breed standard states that the type is more important than the size. A typical male of 49 cm height normally weighs 17 to 19 kilograms (37 to 42 lb), but the breed has a weight range of 15 to 24 kilograms (33 to 53 lb), depending on
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#17328759956242552-407: Is a condition in which months or years after successful cataract surgery, vision deteriorates or problems with glare and light scattering recur, usually due to thickening of the back or posterior capsule surrounding the implanted lens, so-called 'posterior lens capsule opacification'. Growth of natural lens cells remaining after the natural lens was removed may be the cause, and the younger the patient,
2668-532: Is a linear genome made up of homogeneous DNA molecules (type 5). Great variation in mtDNA gene content and size exists among fungi and plants, although there appears to be a core subset of genes present in all eukaryotes (except for the few that have no mitochondria at all). In Fungi, however, there is no single gene shared among all mitogenomes. Some plant species have enormous mitochondrial genomes, with Silene conica mtDNA containing as many as 11,300,000 base pairs. Surprisingly, even those huge mtDNAs contain
2784-561: Is a progressive eye disease that can cause permanent blindness in dogs. In the Finnish Lapphund, this tends to be late onset, but can typically appear between the ages of 1 and 8 years. GPRA is a genetic illness, and is transmitted via an autosomal recessive gene . A reliable genetic test for the prcd-form of GRPA has been developed by OptiGen, and breeders are increasingly testing breeding animals before deciding on suitable mating pairs. The Finnish Lapphund club of Great Britain adopted an ethical policy in 2006 that matings will only be allowed if
2900-737: Is a recognized breed in Finland, the rest of Europe, Australia and the United States. The breed standards are mostly identical, with a few minor exceptions: in the English standard, the acceptance of tipped ears is omitted. The Finnish Lapphund can compete in dog agility trials, carting , mushing , obedience , Rally obedience , showmanship , flyball , tracking , and herding events. Herding instincts and trainability can be measured at non-competitive herding tests. Lapphunds exhibiting basic herding instincts can be trained to compete in herding trials. GPRA
3016-467: Is a well-established marker of oxidative DNA damage. In persons with amyotrophic lateral sclerosis (ALS), the enzymes that normally repair 8-oxoG DNA damages in the mtDNA of spinal motor neurons are impaired. Thus oxidative damage to mtDNA of motor neurons may be a significant factor in the etiology of ALS. Over the past decade, an Israeli research group led by Professor Vadim Fraifeld has shown that strong and significant correlations exist between
3132-591: Is advised to move cautiously and avoid straining or heavy lifting for about a month. The eye is usually patched on the day of surgery and use of an eye shield at night is often suggested for several days after surgery. In all types of surgery, the cataractous lens is removed and replaced with an artificial lens, known as an intraocular lens , which stays in the eye permanently. Intraocular lenses are usually monofocal, correcting for either distance or near vision. Multifocal lenses may be implanted to improve near and distance vision simultaneously, but these lenses may increase
3248-662: Is an autosomal recessive disorder associated with cuneiform cataracts and nuclear sclerosis. Basal-cell nevus and pemphigus have similar associations. Cigarette smoking has been shown to increase the risk of age-related cataract and nuclear cataract. Evidence is conflicting over the effect of alcohol. Some surveys have shown a link, but others that followed people over longer terms have not. Low vitamin C intake and serum levels have been associated with greater cataract rates. However, use of supplements of vitamin C has not demonstrated benefit. Some medications, such as systemic, topical, or inhaled corticosteroids , may increase
3364-507: Is black and tan: a predominantly black dog with tan legs and face. Any colour combination is allowed as long as the primary colour is dominant. Common colourations may include crème, black, red, brown, sable and wolf-sable. In descending order of dominance, the following genes in certain series correspond to specific colourations: A series (Agouti): B series (brown) C series (colour): E series (extension) Many Finnish Lapphunds have very distinctive facial markings, like "spectacles", where
3480-487: Is data supporting the involvement of helix-distorting intrinsically curved regions and long G-tetrads in eliciting instability events. In addition, higher breakpoint densities were consistently observed within GC-skewed regions and in the close vicinity of the degenerate sequence motif YMMYMNNMMHM. Unlike nuclear DNA, which is inherited from both parents and in which genes are rearranged in the process of recombination , there
3596-514: Is observed in bivalve mollusks. In those species, females have only one type of mtDNA (F), whereas males have F type mtDNA in their somatic cells, but M type of mtDNA (which can be as much as 30% divergent) in germline cells. Paternally inherited mitochondria have additionally been reported in some insects such as fruit flies , honeybees , and periodical cicadas . An IVF technique known as mitochondrial donation or mitochondrial replacement therapy (MRT) results in offspring containing mtDNA from
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3712-509: Is one hypothesis for why some genes are retained in mtDNA; colocalisation for redox regulation is another, citing the desirability of localised control over mitochondrial machinery. Recent analysis of a wide range of mtDNA genomes suggests that both these features may dictate mitochondrial gene retention. Across all organisms, there are six main mitochondrial genome types, classified by structure (i.e. circular versus linear), size, presence of introns or plasmid like structures , and whether
3828-429: Is problematic. Manual small incision cataract surgery (MSICS) has evolved from ECCE. In MSICS, the lens is removed through a self-sealing scleral tunnel wound in the sclera which, ideally, is watertight and does not require suturing. Although "small", the incision is still markedly larger than the portal in phacoemulsification. This surgery is increasingly popular in the developing world where access to phacoemulsification
3944-540: Is severely degraded. Autosomal cells only have two copies of nuclear DNA, but can have hundreds of copies of mtDNA due to the multiple mitochondria present in each cell. This means highly degraded evidence that would not be beneficial for STR analysis could be used in mtDNA analysis. mtDNA may be present in bones, teeth, or hair, which could be the only remains left in the case of severe degradation. In contrast to STR analysis, mtDNA sequencing uses Sanger sequencing . The known sequence and questioned sequence are both compared to
4060-414: Is still limited. Intracapsular cataract extraction (ICCE) is rarely performed. The lens and surrounding capsule are removed in one piece through a large incision while pressure is applied to the vitreous membrane . The surgery has a high rate of complications. The postoperative recovery period (after removing the cataract) is usually short. The patient is usually ambulatory on the day of surgery, but
4176-518: Is the DNA located in the mitochondria organelles in a eukaryotic cell that converts chemical energy from food into adenosine triphosphate (ATP). Mitochondrial DNA is a small portion of the DNA contained in a eukaryotic cell; most of the DNA is in the cell nucleus , and, in plants and algae, the DNA also is found in plastids , such as chloroplasts . Human mitochondrial DNA was the first significant part of
4292-485: Is the first multicellular organism known to have this absence of aerobic respiration and live completely free of oxygen dependency. There are three different mitochondrial genome types in plants and fungi. The first type is a circular genome that has introns (type 2) and may range from 19 to 1000 kbp in length. The second genome type is a circular genome (about 20–1000 kbp) that also has a plasmid-like structure (1 kb) (type 3). The final genome type found in plants and fungi
4408-495: Is the only effective treatment. Cataract surgery is not readily available in many countries, and surgery is needed only if the cataracts are causing problems and generally results in an improved quality of life . About 20 million people worldwide are blind due to cataracts. It is the cause of approximately 5% of blindness in the United States and nearly 60% of blindness in parts of Africa and South America. Blindness from cataracts occurs in about 10 to 40 per 100,000 children in
4524-452: Is used in an analogous way to determine the patrilineal history.) This is usually accomplished on human mitochondrial DNA by sequencing the hypervariable control regions (HVR1 or HVR2), and sometimes the complete molecule of the mitochondrial DNA, as a genealogical DNA test . HVR1, for example, consists of about 440 base pairs. These 440 base pairs are compared to the same regions of other individuals (either specific people or subjects in
4640-510: Is usually no change in mtDNA from parent to offspring. Although mtDNA also recombines, it does so with copies of itself within the same mitochondrion. Because of this and because the mutation rate of animal mtDNA is higher than that of nuclear DNA, mtDNA is a powerful tool for tracking ancestry through females ( matrilineage ) and has been used in this role to track the ancestry of many species back hundreds of generations. mtDNA testing can be used by forensic scientists in cases where nuclear DNA
4756-534: Is very small. Other diseases include epilepsy, hypothyroidism (underactive thyroid), degenerative myelopathy (DM) and Pompe disease (also known as glycogen storage disease type II, GSD II), which is a progressive disorder of glycogen metabolism. The breed has its origins as a reindeer herder of the Sami people . The Sami are an indigenous people residing in areas now divided between Finland, Sweden, Norway, and Russia. Traditionally, reindeer herding has been very important for
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4872-517: The POLG2 gene. The replisome machinery is formed by DNA polymerase, TWINKLE and mitochondrial SSB proteins . TWINKLE is a helicase , which unwinds short stretches of dsDNA in the 5' to 3' direction. All these polypeptides are encoded in the nuclear genome. During embryogenesis , replication of mtDNA is strictly down-regulated from the fertilized oocyte through the preimplantation embryo. The resulting reduction in per-cell copy number of mtDNA plays
4988-570: The Crown of Aragon , famously removed the cataracts of King John II of Aragon , restoring his eyesight. "Cataract" is derived from the Latin cataracta , meaning "waterfall", and from the Ancient Greek καταρράκτης ( katarrhaktēs ), "down-rushing", from καταράσσω ( katarassō ) meaning "to dash down" (from kata -, "down"; arassein , "to strike, dash"). As rapidly running water turns white, so
5104-515: The developing world , and 1 to 4 per 100,000 children in the developed world . Cataracts become more common with age . In the United States, cataracts occur in 68% of those over the age of 80 years. Additionally they are more common in women, and less common in Hispanic and Black people. Signs and symptoms vary depending on the type of cataract, though considerable overlap occurs. People with nuclear sclerotic or brunescent cataracts often notice
5220-413: The eukaryotic nucleus during evolution . The reasons mitochondria have retained some genes are debated. The existence in some species of mitochondrion-derived organelles lacking a genome suggests that complete gene loss is possible, and transferring mitochondrial genes to the nucleus has several advantages. The difficulty of targeting remotely-produced hydrophobic protein products to the mitochondrion
5336-586: The human genome to be sequenced. This sequencing revealed that human mtDNA has 16,569 base pairs and encodes 13 proteins . As in other vertebrates, the human mitochondrial genetic code differs slightly from nuclear DNA. Since animal mtDNA evolves faster than nuclear genetic markers, it represents a mainstay of phylogenetics and evolutionary biology . It also permits tracing the relationships of populations, and so has become important in anthropology and biogeography . Nuclear and mitochondrial DNA are thought to have separate evolutionary origins, with
5452-430: The phylogenetic tree is rooted in the same sequence as the 33,000 year-old Altai dog (not a direct ancestor). The Finnish Lapphund is a medium-sized, strongly-built dog. It has a profuse coat with pricked, highly mobile ears, distinctive markings and an elegant nose. Colours include black and cream, black and tan, white and grey, brown and white, brown and cream, as well as pure black, white and gray. The breed standard
5568-466: The 1998 United States court case of Commonwealth of Pennsylvania v. Patricia Lynne Rorrer, mitochondrial DNA was admitted into evidence in the State of Pennsylvania for the first time. The case was featured in episode 55 of season 5 of the true crime drama series Forensic Files (season 5) . Cataracts A cataract is a cloudy area in the lens of the eye that leads to a decrease in vision of
5684-528: The DNA of lens cells. Ultraviolet light, specifically UVB , has also been shown to cause cataracts, and some evidence indicates sunglasses worn at an early age can slow its development in later life. Microwaves , a type of nonionizing radiation , may cause harm by denaturing protective enzymes (e.g., glutathione peroxidase ), by oxidizing protein thiol groups (causing protein aggregation ), or by damaging lens cells via thermoelastic expansion. The protein coagulation caused by electric and heat injuries whitens
5800-739: The Finnish Lapphund standard soon followed. In Finland, the first breed standards were set in 1945 by the Finnish Kennel Club, who called the breed the Lappish Herder, also known as Kukonharjunlainen . It is believed that these dogs were the result of a cross between the Karelian Bear Dog and the reindeer dogs, and had short hair. In the 1950s the Finnish Kennel Association (the second major kennel association in Finland) created
5916-558: The Revised Cambridge Reference Sequence to generate their respective haplotypes. If the known sample sequence and questioned sequence originated from the same matriline, one would expect to see identical sequences and identical differences from the rCRS. Cases arise where there are no known samples to collect and the unknown sequence can be searched in a database such as EMPOP. The Scientific Working Group on DNA Analysis Methods recommends three conclusions for describing
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#17328759956246032-491: The Sami people, and they are still involved in herding today. The Sami have used herding dogs for centuries, and these dogs were typically long in body, somewhat rectangular in shape, with long hair and a straight tail that would curl up over the back when the dog was moving. Finnish Lapphunds are the most similar to the long haired dogs developed by the Sami people in order to assist them with herding, often favoured as winter herders for
6148-543: The accumulation of deleterious mutations until functionality is lost. Animal populations of mitochondria avoid this through a developmental process known as the mtDNA bottleneck . The bottleneck exploits random processes in the cell to increase the cell-to-cell variability in mutant load as an organism develops: a single egg cell with some proportion of mutant mtDNA thus produces an embryo in which different cells have different mutant loads. Cell-level selection may then act to remove those cells with more mutant mtDNA, leading to
6264-419: The accumulation of mtDNA damage in several organs of rats. For example, dietary restriction prevented age-related accumulation of mtDNA damage in the cortex and decreased it in the lung and testis. Increased mt DNA damage is a feature of several neurodegenerative diseases . The brains of individuals with Alzheimer's disease have elevated levels of oxidative DNA damage in both nuclear DNA and mtDNA, but
6380-513: The ages of 75 and 85. Cataracts affect nearly 22 million Americans age 40 and older. By age 80, more than half of all Americans have cataracts. Direct medical costs for cataract treatment are estimated at $ 6.8 billion annually. In the eastern Mediterranean region, cataracts are responsible for over 51% of blindness. Access to eye care in many countries in this region is limited. Childhood-related cataracts are responsible for 5–20% of world childhood blindness. Vision loss due to cataracts increases
6496-452: The back of the lens adjacent to the capsule (or bag) in which the lens sits. Because light becomes more focused toward the back of the lens, they can cause disproportionate symptoms for their size. An immature cataract has some transparent protein, but with a mature cataract, all the lens protein is opaque. In a hypermature or Morgagnian cataract, the lens proteins have become liquid. Congenital cataract, which may be detected in adulthood, has
6612-497: The case of neurofibromatosis type 2 , juvenile cataract on one or both sides may be noted. Examples of single-gene disorder include Alport's syndrome , Conradi's syndrome , cerebrotendineous xanthomatosis , myotonic dystrophy , and oculocerebrorenal syndrome or Lowe syndrome . The skin and the lens have the same embryological origin and so can be affected by similar diseases. Those with atopic dermatitis and eczema occasionally develop shield ulcer cataracts. Ichthyosis
6728-414: The chance of unsatisfactory vision. Serious complications of cataract surgery include retinal detachment and endophthalmitis . In both cases, patients notice a sudden decrease in vision. In endophthalmitis, patients often describe pain. Retinal detachment frequently presents with unilateral visual field defects, blurring of vision, flashes of light, or floating spots. The risk of retinal detachment
6844-456: The coding instructions for some proteins, which may have an effect on organism metabolism and/or fitness. Mutations of mitochondrial DNA can lead to a number of illnesses including exercise intolerance and Kearns–Sayre syndrome (KSS), which causes a person to lose full function of heart, eye, and muscle movements. Some evidence suggests that they might be major contributors to the aging process and age-associated pathologies . Particularly in
6960-714: The context of disease, the proportion of mutant mtDNA molecules in a cell is termed heteroplasmy . The within-cell and between-cell distributions of heteroplasmy dictate the onset and severity of disease and are influenced by complicated stochastic processes within the cell and during development. Mutations in mitochondrial tRNAs can be responsible for severe diseases like the MELAS and MERRF syndromes. Mutations in nuclear genes that encode proteins that mitochondria use can also contribute to mitochondrial diseases. These diseases do not follow mitochondrial inheritance patterns, but instead follow Mendelian inheritance patterns. Recently
7076-403: The differences between a known mtDNA sequence and a questioned mtDNA sequence: exclusion for two or more differences between the sequences, inconclusive if there is one nucleotide difference, or cannot exclude if there are no nucleotide differences between the two sequences. The rapid mutation rate (in animals) makes mtDNA useful for assessing genetic relationships of individuals or groups within
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#17328759956247192-626: The differences in animal species maximum life spans in a multiplicative manner (i.e., species maximum life span = their mtDNA GC% * metabolic rate). To support the scientific community in carrying out comparative analyses between mtDNA features and longevity across animals, a dedicated database was built named MitoAge . De novo mutations arise either due to mistakes during DNA replication or due to unrepaired damage caused in turn by endogenous and exogenous mutagens. It has been long believed that mtDNA can be particularly sensitive to damage caused by reactive oxygen species (ROS), however G>T substitutions,
7308-465: The end stage of the far better known phenomenon of hyperbaric myopic shift. Cataracts may be partial or complete, stationary or progressive, hard or soft. Histologically, the main types of age-related cataracts are nuclear sclerosis, cortical, and posterior subcapsular. Nuclear sclerosis is the most common type of cataract, and involves the central or 'nuclear' part of the lens. This eventually becomes hard, or 'sclerotic', due to condensation on
7424-624: The ends of the linear DNA ) with different modes of replication, which have made them interesting objects of research because many of these unicellular organisms with linear mtDNA are known pathogens . Most ( bilaterian ) animals have a circular mitochondrial genome. Medusozoa and calcarea clades however include species with linear mitochondrial chromosomes. With a few exceptions, animals have 37 genes in their mitochondrial DNA: 13 for proteins , 22 for tRNAs , and 2 for rRNAs . Mitochondrial genomes for animals average about 16,000 base pairs in length. The anemone Isarachnanthus nocturnus has
7540-662: The eye and covering the eye with warm butter . References to cataracts and their treatment in Ancient Rome are also found in 29 AD in De Medicinae , the work of the Latin encyclopedist Aulus Cornelius Celsus . Archaeological evidence of eye surgery in the Roman era also exists. Galen of Pergamon (ca. 2nd century CE), a prominent Greek physician , surgeon and philosopher , performed an operation similar to modern cataract surgery. Using
7656-431: The eye. Oxidative stress associated with lipid peroxidation is an important pathogenic mechanism in cataract formation. Senile cataracts are associated with a decrease in antioxidant capacity in the lens. An increase in oxidative stress in the lens or a decrease in the ability to remove reactive oxygen species can lead to the lens becoming more opaque. Blunt trauma causes swelling, thickening, and whitening of
7772-911: The eye. Cataracts often develop slowly and can affect one or both eyes. Symptoms may include faded colours, blurry or double vision , halos around light, trouble with bright lights, and difficulty seeing at night . This may result in trouble driving, reading, or recognizing faces. Poor vision caused by cataracts may also result in an increased risk of falling and depression . Cataracts cause 51% of all cases of blindness and 33% of visual impairment worldwide. Cataracts are most commonly due to aging but may also occur due to trauma or radiation exposure, be present from birth , or occur following eye surgery for other problems. Risk factors include diabetes , longstanding use of corticosteroid medication, smoking tobacco , prolonged exposure to sunlight , and alcohol . The underlying mechanism involves accumulation of clumps of protein or yellow-brown pigment in
7888-520: The first breed standard for the Lapponian herder . Acceptable colours for this breed were black, bear-brown and white. In the 1960s, the various Finnish kennel associations were unified, and in 1966 the breeds were reassessed. This resulted in the formal definition of two breeds: the Lapponian herder with a shorter coat was defined in 1966, and the longer coated Finnish Lapphund was defined in 1967. At about
8004-403: The genetic distances of distantly related species. Statistical models that treat substitution rates among codon positions separately, can thus be used to simultaneously estimate phylogenies that contain both closely and distantly related species Mitochondrial DNA was admitted into evidence for the first time ever in a United States courtroom in 1996 during State of Tennessee v. Paul Ware . In
8120-422: The genetic material is a singular molecule or collection of homogeneous or heterogeneous molecules. In many unicellular organisms (e.g., the ciliate Tetrahymena and the green alga Chlamydomonas reinhardtii ), and in rare cases also in multicellular organisms (e.g. in some species of Cnidaria ), the mtDNA is linear DNA . Most of these linear mtDNAs possess telomerase -independent telomeres (i.e.,
8236-419: The greater the chance of this occurring. Management involves cutting a small, circular area in the posterior capsule with targeted beams of energy from a laser, called Nd:YAG laser capsulotomy, after the type of laser used. The laser can be aimed very accurately, and the small part of the capsule which is cut falls harmlessly to the bottom of the inside of the eye. This procedure leaves sufficient capsule to hold
8352-477: The hallmark of the oxidative damage in the nuclear genome, are very rare in mtDNA and do not increase with age. Comparing the mtDNA mutational spectra of hundreds of mammalian species, it has been recently demonstrated that species with extended lifespans have an increased rate of A>G substitutions on single-stranded heavy chain. This discovery led to the hypothesis that A>G is a mitochondria-specific marker of age-associated oxidative damage. This finding provides
8468-413: The highest risk group of patients, the incidence of pseudophakic retinal detachment may be as high as 20%. The risk of endophthalmitis occurring after surgery is less than one in 1000. Corneal edema and cystoid macular edema are less serious but more common, and occur because of persistent swelling at the front of the eye in corneal edema or back of the eye in cystoid macular edema. They are normally
8584-421: The human mitochondrial DNA are distinguished as the heavy strand and the light strand. The heavy strand is rich in guanine and encodes 12 subunits of the oxidative phosphorylation system, two ribosomal RNAs (12S and 16S), and 14 transfer RNAs (tRNAs). The light strand encodes one subunit, and 8 tRNAs. So, altogether mtDNA encodes for two rRNAs, 22 tRNAs, and 13 protein subunits , all of which are involved in
8700-524: The idea is controversial, some evidence suggests a link between aging and mitochondrial genome dysfunction. In essence, mutations in mtDNA upset a careful balance of reactive oxygen species (ROS) production and enzymatic ROS scavenging (by enzymes like superoxide dismutase , catalase , glutathione peroxidase and others). However, some mutations that increase ROS production (e.g., by reducing antioxidant defenses) in worms increase, rather than decrease, their longevity. Also, naked mole rats , rodents about
8816-462: The initiation of the transcription of the heavy and light strands are located in the main non-coding region of the mtDNA called the displacement loop, the D-loop . There is evidence that the transcription of the mitochondrial rRNAs is regulated by the heavy-strand promoter 1 (HSP1), and the transcription of the polycistronic transcripts coding for the protein subunits are regulated by HSP2. Measurement of
8932-558: The largest mitochondrial genome of any animal at 80,923 bp. The smallest known mitochondrial genome in animals belongs to the comb jelly Vallicula multiformis , which consist of 9,961 bp. In February 2020, a jellyfish-related parasite – Henneguya salminicola – was discovered that lacks a mitochondrial genome but retains structures deemed mitochondrion-related organelles. Moreover, nuclear DNA genes involved in aerobic respiration and in mitochondrial DNA replication and transcription were either absent or present only as pseudogenes . This
9048-412: The leading cause of blindness. Even where surgical services are available, low vision associated with cataracts may still be prevalent as a result of long waits for, and barriers to, surgery, such as cost, lack of information and transportation problems. In the United States, age-related lens changes have been reported in 42% between the ages of 52 and 64, 60% between the ages 65 and 74, and 91% between
9164-445: The lens and because conventional vitreous substitutes do not contain ascorbic acid. Accordingly, for phakic patients requiring a vitrectomy it is becoming increasingly common for ophthalmologists to offer the vitrectomy combined with prophylactic cataract surgery to prevent cataract formation. Hyperbaric oxygen therapy (HBOT) is the administration of 100% oxygen at pressures greater than one-atmosphere absolute pressure (1 ATA) for
9280-407: The lens cortex (outer layer) becoming opaque. They occur when changes in the fluid contained in the periphery of the lens cause fissuring. When these cataracts are viewed through an ophthalmoscope , or other magnification system, the appearance is similar to white spokes of a wheel. Symptoms often include problems with glare and light scatter at night. Posterior subcapsular cataracts are cloudy at
9396-680: The lens fibers. While the swelling normally resolves with time, the white color may remain. In severe blunt trauma, or in injuries that penetrate the eye, the capsule in which the lens sits can be damaged. This damage allows fluid from other parts of the eye to rapidly enter the lens leading to swelling and then whitening, obstructing light from reaching the retina at the back of the eye. Cataracts may develop in 0.7 to 8.0% of cases following electrical injuries . Blunt trauma can also result in star- (stellate) or petal-shaped cataracts. Cataracts can arise as an effect of exposure to various types of radiation. X-rays, one form of ionizing radiation , may damage
9512-774: The lens in place, but removes enough to allow light to pass directly through to the retina. Serious side effects are rare. Posterior capsular opacification is common and occurs following up to one in four operations, but these rates are decreasing following the introduction of modern intraocular lenses together with a better understanding of the causes. Vitreous touch syndrome is a possible complication of intracapsular cataract extraction. Age-related cataracts are responsible for 51% of world blindness, about 20 million people. Globally, cataracts cause moderate to severe disability in 53.8 million (2004), 52.2 million of whom are in low and middle income countries. In many countries, surgical services are inadequate, and cataracts remain
9628-454: The lens nucleus and the deposition of brown pigment within the lens. In its advanced stages, it is called a brunescent cataract. In early stages, an increase in sclerosis may cause an increase in refractive index of the lens. This causes a myopic shift (lenticular shift) that decreases hyperopia and enables presbyopic patients to see at near without reading glasses. This is only temporary and is called second sight. Cortical cataracts are due to
9744-448: The lens that reduces transmission of light to the retina at the back of the eye. Diagnosis is by an eye examination . Wearing sunglasses and a wide brimmed hat, eating leafy vegetables and fruits, and avoiding smoking may reduce the risk of developing cataracts, or slow the process. Early on, the symptoms may be improved with glasses . If this does not help, surgery to remove the cloudy lens and replace it with an artificial lens
9860-496: The lens. Surgery is usually outpatient and usually performed using local anesthesia . About 9 of 10 patients can achieve a corrected vision of 20/40 or better after surgery. Several recent evaluations found that cataract surgery can meet expectations only when significant functional impairment due to cataracts exists before surgery. Visual function estimates such as VF-14 have been found to give more realistic estimates than visual acuity testing alone. In some developed countries,
9976-581: The lens. This same process is what makes the clear albumen of an egg become white and opaque during cooking. The genetic component is strong in the development of cataracts, most commonly through mechanisms that protect and maintain the lens. The presence of cataracts in childhood or early life can occasionally be due to a particular syndrome. Examples of chromosome abnormalities associated with cataracts include 1q21.1 deletion syndrome , cri-du-chat syndrome , Down syndrome , Patau's syndrome , trisomy 18 ( Edward's syndrome ), and Turner's syndrome , and in
10092-415: The levels of the mtDNA-encoded RNAs in bovine tissues has shown that there are major differences in the expression of the mitochondrial RNAs relative to total tissue RNA. Among the 12 tissues examined the highest level of expression was observed in heart, followed by brain and steroidogenic tissue samples. As demonstrated by the effect of the trophic hormone ACTH on adrenal cortex cells, the expression of
10208-443: The longevity of species. The application of a mitochondrial-specific ROS scavenger, which lead to a significant longevity of the mice studied, suggests that mitochondria may still be well-implicated in ageing. Extensive research is being conducted to further investigate this link and methods to combat ageing. Presently, gene therapy and nutraceutical supplementation are popular areas of ongoing research. Bjelakovic et al. analyzed
10324-424: The male-inherited mitochondria were subsequently rejected. It has also been found in sheep, and in cloned cattle. Rare cases of male mitochondrial inheritance have been documented in humans. Although many of these cases involve cloned embryos or subsequent rejection of the paternal mitochondria, others document in vivo inheritance and persistence under lab conditions. Doubly uniparental inheritance of mtDNA
10440-525: The mitochondrial genes may be strongly regulated by external factors, apparently to enhance the synthesis of mitochondrial proteins necessary for energy production. Interestingly, while the expression of protein-encoding genes was stimulated by ACTH, the levels of the mitochondrial 16S rRNA showed no significant change. In most multicellular organisms , mtDNA is inherited from the mother (maternally inherited). Mechanisms for this include simple dilution (an egg contains on average 200,000 mtDNA molecules, whereas
10556-480: The mtDNA base composition and animal species-specific maximum life spans. As demonstrated in their work, higher mtDNA guanine + cytosine content ( GC% ) strongly associates with longer maximum life spans across animal species. An additional observation is that the mtDNA GC% correlation with the maximum life spans is independent of the well-known correlation between animal species metabolic rate and maximum life spans. The mtDNA GC% and resting metabolic rate explain
10672-448: The mtDNA derived from the circular genomes of bacteria engulfed by the ancestors of modern eukaryotic cells. This theory is called the endosymbiotic theory . In the cells of extant organisms, the vast majority of the proteins in the mitochondria (numbering approximately 1500 different types in mammals ) are coded by nuclear DNA , but the genes for some, if not most, of them are thought to be of bacterial origin, having been transferred to
10788-833: The mtDNA has approximately 10-fold higher levels than nuclear DNA. It has been proposed that aged mitochondria is the critical factor in the origin of neurodegeneration in Alzheimer's disease. Analysis of the brains of AD patients suggested an impaired function of the DNA repair pathway, which would cause reduce the overall quality of mtDNA. In Huntington's disease , mutant huntingtin protein causes mitochondrial dysfunction involving inhibition of mitochondrial electron transport , higher levels of reactive oxygen species and increased oxidative stress . Mutant huntingtin protein promotes oxidative damage to mtDNA, as well as nuclear DNA, that may contribute to Huntington's disease pathology . The DNA oxidation product 8-oxoguanine (8-oxoG)
10904-558: The mtDNAs were taken. mtDNA can be used to estimate the relationship between both closely related and distantly related species. Due to the high mutation rate of mtDNA in animals, the 3rd positions of the codons change relatively rapidly, and thus provide information about the genetic distances among closely related individuals or species. On the other hand, the substitution rate of mt-proteins is very low, thus amino acid changes accumulate slowly (with corresponding slow changes at 1st and 2nd codon positions) and thus they provide information about
11020-472: The nucleus. mtDNA is packaged with proteins which appear to be as protective as proteins of the nuclear chromatin. Moreover, mitochondria evolved a unique mechanism which maintains mtDNA integrity through degradation of excessively damaged genomes followed by replication of intact/repaired mtDNA. This mechanism is not present in the nucleus and is enabled by multiple copies of mtDNA present in mitochondria. The outcome of mutation in mtDNA may be an alteration in
11136-487: The oxidative phosphorylation process. Between most (but not all) protein-coding regions, tRNAs are present (see the human mitochondrial genome map ). During transcription, the tRNAs acquire their characteristic L-shape that gets recognized and cleaved by specific enzymes. With the mitochondrial RNA processing, individual mRNA, rRNA, and tRNA sequences are released from the primary transcript. Folded tRNAs therefore act as secondary structure punctuations. The promoters for
11252-466: The plant and fungal genomes also exist in some protists, as do two unique genome types. One of these unique types is a heterogeneous collection of circular DNA molecules (type 4) while the other is a heterogeneous collection of linear molecules (type 6). Genome types 4 and 6 each range from 1–200 kbp in size. The smallest mitochondrial genome sequenced to date is the 5,967 bp mtDNA of the parasite Plasmodium falciparum . Endosymbiotic gene transfer,
11368-495: The process by which genes that were coded in the mitochondrial genome are transferred to the cell's main genome, likely explains why more complex organisms such as humans have smaller mitochondrial genomes than simpler organisms such as protists. Mitochondrial DNA is replicated by the DNA polymerase gamma complex which is composed of a 140 kDa catalytic DNA polymerase encoded by the POLG gene and two 55 kDa accessory subunits encoded by
11484-469: The progeny can not be affected by GPRA. In 2001, 2.5% dogs of Finnish dogs were affected by PRA. Some Lapphunds are affected by cataracts , with 3.4% of Finnish dogs affected. Cataracts can be caused by a number of factors, and the mode of inheritance is not yet well understood. Since the incidence in Finland is relatively high, the disease is considered to be hereditary. In the UK and USA the number of affected dogs
11600-440: The range from ≤ 1.5 mm to 3.0 mm. Extracapsular cataract extraction (ECCE) consists of removing the lens manually, but leaving the majority of the capsule intact. The lens is expressed through a 10- to 12-mm incision which is closed with sutures at the end of surgery. ECCE is less frequently performed than phacoemulsification, but can be useful when dealing with very hard cataracts or other situations where emulsification
11716-507: The reindeer. Norwegians and Swedes were among the first to consider standardizing the dogs of Lapland prior to World War II. In the post war years, the dogs of Lapland were at serious risk due to distemper outbreak. Swedish Lapphund breeders today believe that their breed, and other Lapphund breeds, were in serious danger of extinction. A standard for the related Swedish Lapphund was adopted in 1944 in FCI ( Fédération Cynologique Internationale ), and
11832-419: The result of excessive inflammation following surgery, and in both cases, patients may notice blurred, foggy vision. They normally improve with time and with application of anti-inflammatory drops. The risk of either occurring is around one in 100. It is unclear whether NSAIDs or corticosteroids are superior at reducing postoperative inflammation. Posterior capsular opacification, also known as after-cataract,
11948-409: The results of 78 studies between 1977 and 2012, involving a total of 296,707 participants, and concluded that antioxidant supplements do not reduce all-cause mortality nor extend lifespan, while some of them, such as beta carotene, vitamin E, and higher doses of vitamin A, may actually increase mortality. In a recent study, it was shown that dietary restriction can reverse ageing alterations by affecting
12064-415: The risk of cataract development. Corticosteroids most commonly cause posterior subcapsular cataracts. People with schizophrenia often have risk factors for lens opacities (such as diabetes, hypertension, and poor nutrition). Second-generation antipsychotic medications are unlikely to contribute to cataract formation. Miotics and triparanol may increase the risk. Nearly every person who undergoes
12180-421: The risk of cataracts, clinical trials have shown no benefit from supplements, although the evidence is mixed, but weakly positive, for a potential protective effect of the carotenoids , lutein and zeaxanthin . The appropriateness of surgery depends on a person's particular functional and visual needs and other risk factors. Cataract removal can be performed at any stage and no longer requires ripening of
12296-526: The risk of dementia in the elderly population, increases the likelihood of falls and road traffic accidents, and by detrimental effects on the quality of life increases mortality. Cataract surgery was first described by the Ayurvedic physician , Suśruta (about 5th century BCE) in Sushruta Samhita in ancient India . Most of the methods mentioned focus on hygiene. Follow-up treatments include bandaging of
12412-442: The same number and kinds of genes as related plants with much smaller mtDNAs. The genome of the mitochondrion of the cucumber ( Cucumis sativus ) consists of three circular chromosomes (lengths 1556, 84 and 45 kilobases), which are entirely or largely autonomous with regard to their replication . Protists contain the most diverse mitochondrial genomes, with five different types found in this kingdom. Type 2, type 3 and type 5 of
12528-444: The same time, technology enabled changes in the lifestyle of the Sami herders. Previously, the longer-haired dogs were generally preferred for herding, but with the advent of snowmobiles , the preference started to change in favour of the shorter haired Lapponian herder. However, popularity did not die for the longer-haired breed, which as of 2014 was ranked the sixth most popular companion animal in Finland. The first American litter
12644-500: The size of mice , live about eight times longer than mice despite having reduced, compared to mice, antioxidant defenses and increased oxidative damage to biomolecules. Once, there was thought to be a positive feedback loop at work (a 'Vicious Cycle'); as mitochondrial DNA accumulates genetic damage caused by free radicals, the mitochondria lose function and leak free radicals into the cytosol . A decrease in mitochondrial function reduces overall metabolic efficiency. However, this concept
12760-481: The size of the dog. The Lapphund has a profuse double coat , with a short, fluffy undercoat and a longer topcoat. The coat is water-resistant, as well as resistant to extreme cold. They also can get very hot. In Finland, only two dog breeds are legally allowed to be kennelled outdoors in winter: the Finnish Lapphund and the Lapponian Herder . The profuse hair around the head and neck give the distinct impression of
12876-519: The term may have been used metaphorically to describe the similar appearance of mature ocular opacities. In Latin, cataracta had the alternative meaning " portcullis " and the name possibly passed through French to form the English meaning "eye disease" (early 15th century), on the notion of "obstruction". Early Persian physicians called the term nazul-i-ah , or "descent of the water"—vulgarised into waterfall disease or cataract—believing such blindness to be caused by an outpouring of corrupt humour into
12992-812: Was born in 1988. In 1994, the breed was recognised by the United Kennel Club (UKC), the second largest kennel club in America, in the Northern Group. The breed was accepted into the AKC Miscellaneous Group on July 1, 2009, and became a fully recognized breed in the Herding Group on June 30, 2011. The Finnish Lapphund Club of America (FLCA) is the parent organization in the United States and was awarded parent club status on November 25, 2015, thus allowing it to hold licensed championship point events. The breed
13108-410: Was conclusively disproved when it was demonstrated that mice, which were genetically altered to accumulate mtDNA mutations at accelerated rate do age prematurely, but their tissues do not produce more ROS as predicted by the 'Vicious Cycle' hypothesis. Supporting a link between longevity and mitochondrial DNA, some studies have found correlations between biochemical properties of the mitochondrial DNA and
13224-434: Was estimated as about 0.4% within 5.5 years, corresponding to a 2.3-fold risk increase compared to naturally expected incidence, with older studies reporting a substantially higher risk. The incidence is increasing over time in a somewhat linear manner, and the risk increase lasts for at least 20 years after the procedure. Particular risk factors are younger age, male sex, longer axial length, and complications during surgery. In
13340-597: Was first introduced to the United Kingdom in 1989 and is represented by the Finnish Lapphund Club of Great Britain. It was introduced to Australia and Canada in 1995 and is accepted by the New Zealand Kennel Club and Canadian Kennel Club. In Canada, its parent club is the Finnish Lapphund Club of Canada. Books Further reading Mitochondrial DNA Mitochondrial DNA ( mtDNA and mDNA )
13456-460: Was reported that paternal sperm mitochondria (containing mtDNA) are marked with ubiquitin to select them for later destruction inside the embryo . Some in vitro fertilization techniques, particularly injecting a sperm into an oocyte , may interfere with this. The fact that mitochondrial DNA is mostly maternally inherited enables genealogical researchers to trace maternal lineage far back in time. ( Y-chromosomal DNA , paternally inherited,
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