Canid hybrids are the result of interbreeding between the species of the subfamily Caninae .
114-704: The wolf-like canids are a group of large carnivores that are genetically closely related because they all possess 78 chromosomes , arranged in 39 pairs and are karyologically indistinguishable from each other. The group includes the genera Canis , Cuon , Lupulella and Lycaon . The members are the domestic dog (C. lupus familiaris) , gray wolf ( C. lupus ), dingo ( C. lupus dingo ), coyote ( C. latrans ), golden jackal ( C. aureus ), African wolf ( C. lupaster ), Ethiopian wolf ( C. simensis ), dhole ( Cuon alpinus ), black-backed jackal ( Lupulella mesomelas ), side-striped jackal ( L. adusta ) and African wild dog ( Lycaon pictus ). Newly proposed members include
228-455: A 'metaphase chromosome') is highly condensed and thus easiest to distinguish and study. In animal cells, chromosomes reach their highest compaction level in anaphase during chromosome segregation . Chromosomal recombination during meiosis and subsequent sexual reproduction plays a crucial role in genetic diversity . If these structures are manipulated incorrectly, through processes known as chromosomal instability and translocation ,
342-459: A cell nucleus. Chromosomes in humans can be divided into two types: autosomes (body chromosome(s)) and allosome ( sex chromosome (s)). Certain genetic traits are linked to a person's sex and are passed on through the sex chromosomes. The autosomes contain the rest of the genetic hereditary information. All act in the same way during cell division. Human cells have 23 pairs of chromosomes (22 pairs of autosomes and one pair of sex chromosomes), giving
456-488: A classic "saddle" to an overall "blanket". Rarer colour variations include sable, pure-black, pure-white , liver, silver, blue, and panda varieties. The all-black and sable varieties are acceptable according to most standards; however, the blue and liver are considered to be serious faults and the all-white is grounds for instant disqualification from showing in conformation at All Breed and Specialty Shows. German Shepherds were bred specifically for their intelligence . In
570-441: A female hybrid from an English dog and jackal, which even in this the first generation was so sterile that, as I was assured by her keeper, she did not fully exhibit her proper periods; but this case, from numerous instances have occurred of fertile hybrids from these two animals, was certainly exceptional. Crossings between canids of a different genus is extremely rare. In 2021, a female canid with unusual phenotypic characteristics
684-532: A genetic link. It is believed the society accomplished its goal mostly due to von Stephanitz's strong, uncompromising leadership and he is therefore credited with being the creator of the German Shepherd Dog. During the first half of the twentieth century, the breed came to be strongly identified with Imperial and Nazi Germany, because of its association with purity and militarism. German Shepherds were coveted as " germanische Urhunde ", being close to
798-438: A gray wolf–coyote hybrid (Nowak 2002). Therefore, while the red wolf's taxonomic status remains unclear, there is mounting evidence to support C. rufus as a unique canid taxon. Classifying animals commonly referred to as " eastern coyotes " or " northeastern coyotes " has become a problem for taxonomists, as it is unclear what new taxon will be used to refer to this new population of animals. The Ethiopian wolf 's conservation
912-458: A haploid number of seven chromosomes, still seen in some cultivars as well as the wild progenitors. The more common types of pasta and bread are polyploid, having 28 (tetraploid) and 42 (hexaploid) chromosomes, compared to the 14 (diploid) chromosomes in wild wheat. German Shepherd This is an accepted version of this page The German Shepherd , also known in Britain as an Alsatian ,
1026-489: A higher chance of bearing a child with a chromosome disorder. Abnormal numbers of chromosomes or chromosome sets, called aneuploidy , may be lethal or may give rise to genetic disorders. Genetic counseling is offered for families that may carry a chromosome rearrangement. The gain or loss of DNA from chromosomes can lead to a variety of genetic disorders . Human examples include: Exposure of males to certain lifestyle, environmental and/or occupational hazards may increase
1140-483: A life expectancy of 10 years, the same as the overall but less than the 11 year average for crossbreeds; a 2005 study in Sweden based on insurance data found 51% of German Shepherd dogs died by the age of 10, lower than the overall rate of 10 year survival at 35%. A 2015 French study found a life expectancy of 10.08 years. The German Shepherd Dog is one of the breeds more commonly affected by degenerative myelopathy , which
1254-431: A list of breeds most likely to bark as watchdogs, Stanley Coren ranked the breed in second place. Coupled with their strength, this trait makes the breed desirable as police , guard and search and rescue dogs , as they are able to quickly learn various tasks and interpret instructions better than other breeds. German Shepherds are moderately active dogs and are described in breed standards as self assured. The breed
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#17330856332711368-480: A narrower sense, 'chromosome' can be used to refer to the individualized portions of chromatin during cell division, which are visible under light microscopy due to high condensation. The word chromosome ( / ˈ k r oʊ m ə ˌ s oʊ m , - ˌ z oʊ m / ) comes from the Greek words χρῶμα ( chroma , "colour") and σῶμα ( soma , "body"), describing the strong staining produced by particular dyes . The term
1482-486: A popular selection for use as working dogs . They are known for being easy to train and good for performing tasks and following instructions. They are especially well known for their police work, being used for tracking criminals, patrolling troubled areas and detection and holding of suspects. Additionally, thousands of German Shepherds have been used by the military. These military working dogs (MWD) are usually trained for scout duty, and they are used to warn soldiers to
1596-535: A position it has maintained to this day. By 1923, the Verein für Deutsche Schäferhunde claimed 50,000 dues-paying members in more than 500 branches in Germany alone. Horand became the center-point of the breeding programs and was bred with dogs belonging to other society members that displayed desirable traits and with dogs from Thuringia , Franconia , and Württemberg . Fathering many pups, Horand's most prolific
1710-619: A problem for canid taxonomy, as hybrids are not normally thought of as species, though the convention is to continue to refer to red wolves as a subspecies of the gray wolf, Canis lupus rufus , with no mention of the coyote taxon latrans . In recent history, the taxonomic status of the red wolf has been widely debated. Mech (1970) suggested that red wolves may be fertile hybrid offspring from gray wolf ( Canis lupus ) and coyote ( C. latrans ) interbreeding. Wayne and Jenks (1991) and Roy et al. (1994b, 1996) supported this suggestion with genetic analysis. Phillips and Henry (1992) present logic supporting
1824-481: A semi-ordered structure, where it is wrapped around histones (structural proteins), forming a composite material called chromatin. The packaging of DNA into nucleosomes causes a 10 nanometer fibre which may further condense up to 30 nm fibres Most of the euchromatin in interphase nuclei appears to be in the form of 30-nm fibers. Chromatin structure is the more decondensed state, i.e. the 10-nm conformation allows transcription. During interphase (the period of
1938-409: A separate species, C. lycaon , with their minor differences acknowledged via subspecies designation. North American wolf biologists and geneticists also concluded that C. rufus and C. lupus lycaon were genetically more similar to each other than either was to C. lupus or C. latrans (B. T. Kelly, unpubl.). In 2002, morphometric analyses of skulls also indicate that the red wolf is likely not to be
2052-418: A series of experiments beginning in the mid-1880s, Theodor Boveri gave definitive contributions to elucidating that chromosomes are the vectors of heredity , with two notions that became known as 'chromosome continuity' and 'chromosome individuality'. Wilhelm Roux suggested that every chromosome carries a different genetic configuration , and Boveri was able to test and confirm this hypothesis. Aided by
2166-399: A standard weight range. They have a domed forehead, a long square-cut muzzle with strong jaws and a black nose. The eyes are medium-sized and brown. The ears are large and stand erect, open at the front and parallel, but they often are pulled back during movement. A German Shepherd has a long neck, which is raised when excited and lowered when moving at a fast pace as well as stalking. The tail
2280-568: A study of the maternal mitochondrial DNA of the black-backed jackal could find no evidence of genotypes from its most likely mate, the side-striped jackal, indicating that male black-backed jackals had not bred with their sister species. When the differences in number and arrangement of chromosomes is too great, hybridization becomes less and less likely. Other members of the wider dog family, Canidae , such as South American canids , true foxes , bat-eared foxes , or raccoon dogs which diverged 7 to 10 million years ago, are less closely related to
2394-542: A total of 46 per cell. In addition to these, human cells have many hundreds of copies of the mitochondrial genome . Sequencing of the human genome has provided a great deal of information about each of the chromosomes. Below is a table compiling statistics for the chromosomes, based on the Sanger Institute 's human genome information in the Vertebrate Genome Annotation (VEGA) database . Number of genes
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#17330856332712508-440: Is hexaploid , having six copies of seven different chromosome types for a total of 42 chromosomes. Normal members of a particular eukaryotic species all have the same number of nuclear chromosomes. Other eukaryotic chromosomes, i.e., mitochondrial and plasmid-like small chromosomes, are much more variable in number, and there may be thousands of copies per cell. Asexually reproducing species have one set of chromosomes that are
2622-431: Is a German breed of working dog of medium to large size. The breed was developed by Max von Stephanitz using various traditional German herding dogs from 1899. It was originally bred as a herding dog , for herding sheep . It has since been used in many other types of work, including disability assistance , search-and-rescue , police work , and warfare . It is commonly kept as a companion dog , and according to
2736-666: Is a variety of the German Shepherd bred in Switzerland. It descends from the American White Shepherds; the first stud dog of what was to become the breed was an American dog born in 1966 and imported to Switzerland. The variety was recognised by the Fédération Cynologique Internationale as a separate breed in 2003, and it is now recognised by a number of national kennel clubs . German Shepherds are
2850-734: Is a variety of the German Shepherd bred in the United States. White-coated German Shepherds were once banned from registration in their native Germany, but in the United States and Canada the coloration gained a following and a breed club was formed specifically for white German Shepherds, calling their variety the White Shepherd. The variety is recognised as a separate breed by the United Kennel Club . The White Swiss Shepherd Dog ( French : Berger Blanc Suisse , German : Weisser Schweizer Schäferhund , Italian : Pastore Svizzero Bianco )
2964-413: Is an estimate, as it is in part based on gene predictions . Total chromosome length is an estimate as well, based on the estimated size of unsequenced heterochromatin regions. Based on the micrographic characteristics of size, position of the centromere and sometimes the presence of a chromosomal satellite , the human chromosomes are classified into the following groups: In general, the karyotype
3078-405: Is as follows: 1-49% is considered low content (LC), 50-74% is considered to be mid-content (MC), and 75% and higher is considered to be high content (HC). The percentage of the amount of wolf in a wolfdog decides what the animal will look like. For example, if a wolfdog is 25% husky and 75% wolf, it will appear more like a wolf than a husky because it contains more genes from the wolf. This means that
3192-403: Is bushy and reaches to the hock . German Shepherds have a double coat which is close and dense with a thick undercoat. The coat is accepted in two variants: medium and long. The gene for long hair is recessive , and therefore the long-haired variety is rarer. Treatment of the long-haired variation differs across standards; it is accepted but does not compete against standard-coated dogs under
3306-495: Is caused by a mutation in the SOD1 gene. A small study in the UK showed 16% of young asymptomatic German Shepherds to be homozygous for the mutation, with a further 38% being carriers. German Shepherds have a higher-than-normal incidence of Von Willebrand disease , a common inherited bleeding disorder, and exocrine pancreatic insufficiency (EPI), a degenerative disease of the pancreas . It
3420-534: Is controversial, with opponents purporting that it produces an animal unfit as a domestic pet. A number of wolfdog breeds are in development. The first generation crosses (one wolf parent, one dog parent) generally are backcrossed to domestic dogs to maintain a domestic temperament and consistent conformation. The dingo ( Canis lupus dingo ) breeds freely with other domestic dogs. This is now so widespread that in some areas, dingoes are now mostly mixed-breed dogs , crossed in recent times with dogs from other parts of
3534-502: Is criticised by experts for straying away from Max von Stephanitz 's original ideology that German Shepherds should be bred primarily as working dogs and that breeding should be strictly controlled to eliminate defects quickly. He believed that, above all else, German Shepherds should be bred for intelligence and working ability. The Kennel Club , in the United Kingdom, is involved in a dispute with German Shepherd breed clubs about
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3648-459: Is estimated that 1% of the UK population of German Shepherds has this disease. Musculoskeletal disorders are debilitating conditions that are often associated with genetic makeup, malnutrition, and stress-related events. Some breeds like the German Shepherd, are predisposed to a variety of different skeletal disorders, including but not limited to: canine hip dysplasia, Cauda equina syndrome , and osteoarthritis . Canine hip dysplasia (CHD)
3762-598: Is marked by a willingness to learn and an eagerness to have a purpose. They are curious, which makes them excellent guard dogs and suitable for search missions. They can become overprotective of their family and territory, especially if not socialised correctly. They are not inclined to become immediate friends with strangers. German Shepherds are highly intelligent and obedient, as well as protective of their owners. A 2020 literature review in Plastic and Reconstructive Surgery found that from 1971 to 2018, of all pure breed dogs in
3876-605: Is organized into a structure called the nucleoid . The nucleoid is a distinct structure and occupies a defined region of the bacterial cell. This structure is, however, dynamic and is maintained and remodeled by the actions of a range of histone-like proteins, which associate with the bacterial chromosome. In archaea , the DNA in chromosomes is even more organized, with the DNA packaged within structures similar to eukaryotic nucleosomes. Certain bacteria also contain plasmids or other extrachromosomal DNA . These are circular structures in
3990-544: Is present on each sister chromatid . A special DNA base sequence in the region of the kinetochores provides, along with special proteins, longer-lasting attachment in this region. The microtubules then pull the chromatids apart toward the centrosomes, so that each daughter cell inherits one set of chromatids. Once the cells have divided, the chromatids are uncoiled and DNA can again be transcribed. In spite of their appearance, chromosomes are structurally highly condensed, which enables these giant DNA structures to be contained within
4104-412: Is responsible for the condition. The University of Utrecht offers a genetic test for this defect. Untreated dogs usually live between 3-5 years. Dogs that undergo treatment can live healthily for several years but are still unlikely to have a normal life expectancy. German Shepherds have been featured in a wide range of media. In 1921 Strongheart became one of the earliest canine film stars, and
4218-426: Is retained into adulthood and guard hairs fail to fully develop outside of the distal extremities. Eventually full alopecia occurs. The degree of growth retardation and other clinical symptoms varies between affected dogs. Investigations into the genealogy in 1978 found the mutation evolved in 1940 or earlier. Multiple champions have been shown to be carriers of the mutation, explaining the spread and prevalence of
4332-413: Is significant variation within species. Often there is: Also, variation in karyotype may occur during development from the fertilized egg. The technique of determining the karyotype is usually called karyotyping . Cells can be locked part-way through division (in metaphase) in vitro (in a reaction vial) with colchicine . These cells are then stained, photographed, and arranged into a karyogram , with
4446-402: Is that "this issue of soundness is not a simple difference of opinion, it is the fundamental issue of the breed's essential conformation and movement." The Kennel Club has decided to retrain judges to penalise dogs with these problems. The Kennel Club also recommends testing for haemophilia and hip dysplasia, other common problems with the breed. The East-European Shepherd is a variety of
4560-460: Is the abnormal formation of the hip joint and surrounding tissue causing instability and partial dislocation of the hip joint, resulting in pain, inflammation , lameness, and potentially osteoarthritis of the joint. A North American study analysing more than 1,000,000 hip and 250,000 elbow scans in dogs over the age of two found the German Shepherd Dog to have a rate of hip and elbow dysplasia to be 18.9% and 17.8% respectively. The German Shepherd had
4674-425: Is the characteristic chromosome complement of a eukaryote species . The preparation and study of karyotypes is part of cytogenetics . Although the replication and transcription of DNA is highly standardized in eukaryotes, the same cannot be said for their karyotypes, which are often highly variable. There may be variation between species in chromosome number and in detailed organization. In some cases, there
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4788-429: Is the only natural context in which individual chromosomes are visible with an optical microscope . Mitotic metaphase chromosomes are best described by a linearly organized longitudinally compressed array of consecutive chromatin loops. During mitosis, microtubules grow from centrosomes located at opposite ends of the cell and also attach to the centromere at specialized structures called kinetochores , one of which
4902-469: Is threatened by dog hybridisation. Animals resulting from Ethiopian wolf-dog hybridisation tend to be more heavily built than pure wolves, and have shorter muzzles and different coat patterns. Management plans for hybridization with dogs involve sterilization of known hybrids. Incidences of Ethiopian wolf-dog hybridization have been recorded in Bale's Web Valley. At least four hybrids were identified and sterilized in
5016-408: The Fédération Cynologique Internationale had the second-highest number of annual registrations in 2013. During the 1890s, attempts were being made to standardise dog breeds. Dogs were being bred to preserve traits that assisted in their job of herding sheep and protecting their flocks from predators. In Germany this was practised within local communities, where shepherds selected and bred dogs. It
5130-538: The German and UK Kennel Clubs while it can compete with standard-coated dogs, but is considered a fault, in the American Kennel Club. The FCI accepted the long-haired type in 2010, listing it as the variety b, while the short-haired type is listed as the variety a. Most commonly, German Shepherds are either tan/black or red/black. Most colour varieties have black masks and black body markings which can range from
5244-515: The National Geographic Channel television show Dangerous Encounters , the bite of a German Shepherd has a force of over 1,060 newtons (238 lbf) (compared with that of a Rottweiler , over 1,180–1,460 newtons (265–328 lbf), a Pit bull , 1,050 newtons (235 lbf), a Labrador Retriever , of approximately 1,000 newtons (230 lbf), or a human, of approximately 380 newtons (86 lbf)). The modern German Shepherd breed
5358-580: The Reich Chancellery stated in 2005 that Blondi's death had affected the people in the bunker more than Eva Braun 's suicide. German Shepherds were also used widely as guard dogs at Nazi concentration camps during the Holocaust . When the German Shepherd was introduced to the United States it was initially a popular dog. But as the dogs' popularity grew, it became associated as a dangerous breed owned by gangsters and bootleggers . The reputation of
5472-547: The UK Kennel accepted registrations in 1919, 54 German Shepherds were registered. By 1926 this number had grown to over 8000. The breed gained international recognition after the end of World War I. Returning soldiers spoke highly of the breed and animal actors Rin Tin Tin and Strongheart popularised the breed further. The first German Shepherd Dog registered in the United States was Queen of Switzerland. Her offspring had defects as
5586-437: The cell cycle where the cell is not dividing), two types of chromatin can be distinguished: In the early stages of mitosis or meiosis (cell division), the chromatin double helix becomes more and more condensed. They cease to function as accessible genetic material ( transcription stops) and become a compact transportable form. The loops of thirty-nanometer chromatin fibers are thought to fold upon themselves further to form
5700-502: The cytoplasm that contain cellular DNA and play a role in horizontal gene transfer . In prokaryotes and viruses, the DNA is often densely packed and organized; in the case of archaea, by homology to eukaryotic histones, and in the case of bacteria, by histone-like proteins. Bacterial chromosomes tend to be tethered to the plasma membrane of the bacteria. In molecular biology application, this allows for its isolation from plasmid DNA by centrifugation of lysed bacteria and pelleting of
5814-416: The dingo ( Canis lupus dingo ). Therefore, crosses between these species are biologically unremarkable and not a hybridization in the same sense as an interbreeding between different species of Canidae . Wolves are different from domestic dogs in that wolves usually have slimmer chests, longer legs, and they also have stronger jaws than those of the domestic dog subspecies. The difference in appearance from
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#17330856332715928-451: The endosymbiotic bacteria Candidatus Hodgkinia cicadicola and Candidatus Tremblaya princeps , to more than 14,000,000 base pairs in the soil-dwelling bacterium Sorangium cellulosum . Some bacteria have more than one chromosome. For instance, Spirochaetes such as Borrelia burgdorferi (causing Lyme disease ), contain a single linear chromosome. Vibrios typically carry two chromosomes of very different size. Genomes of
6042-545: The red wolf ( Canis rufus ), and the eastern wolf ( Canis lycaon ), subject to a resolution of the dispute as to whether these constitute separate species in their own right or whether they are sub-species of the gray wolf. The members of Canis can potentially interbreed , however, it is believed that Cuon, Lupulella and Lycaon cannot breed with each other or with Canis . The Lupulella genus (the side-striped jackal and black-backed jackal ), could theoretically interbreed with each other to produce fertile offspring, but
6156-563: The 16 chromosomes of yeast were fused into one giant chromosome, it was found that the cells were still viable with only somewhat reduced growth rates. The tables below give the total number of chromosomes (including sex chromosomes) in a cell nucleus for various eukaryotes. Most are diploid , such as humans who have 22 different types of autosomes —each present as two homologous pairs—and two sex chromosomes , giving 46 chromosomes in total. Some other organisms have more than two copies of their chromosome types, for example bread wheat which
6270-449: The 8th highest rate of hip dysplasia and 6th highest rate of elbow dysplasia. Another North American study found 10.26% of German Shepherd Dogs surveyed at teaching hospitals to have hip dysplasia, compared to 3.52% overall. Congenital hyposomatotropism , also known as pituitary dwarfism has been known to be an autosomal recessive disorder in the German Shepherd dog for a long time. The condition causes growth retardation. The puppy coat
6384-447: The German Shepherd bred in the former Soviet Union with the purpose of creating a larger, more cold-resistant version of the German Shepherd. It lacks the physical deformities bred into western show lines of German Shepherds and has become one of Russia's most popular dog types. The King Shepherd is a variety of the German Shepherd bred in the United States, its breeders hoping to rectify the physical deformities that have been bred into
6498-602: The German Shepherd was the breed chosen almost exclusively to be used as a guide dog for the visually impaired . When formal guide dog training began in Switzerland in the 1920s under the leadership of Dorothy Eustis , all of the dogs trained were German Shepherd females. An experiment in temperament testing of a group of Labrador Retrievers and German Shepherds showed that the Retrievers scored higher on average in emotional stability, ability to recover promptly from frightening situations, cooperative behaviour and friendliness; while
6612-718: The German Shepherds as a dangerous breed had grown to such an extent that it was briefly banned to import them in Australia in 1929. Potential legislation was even considered to require that all German shepherds in South Australia be sterilised. The breed was named Deutscher Schäferhund , by von Stephanitz, translating to "German Shepherd Dog". At the time, all other herding dogs in Germany were referred to by this name; they thus became known as Altdeutsche Schäferhunde , or old German herding dogs . The direct translation of
6726-447: The German Shepherds were superior in aggression and defensive behaviour. These results suggested that Labrador Retrievers were more suited to guide dog work while German Shepherds were more suited to police work. Currently, Labradors and Golden Retrievers are more widely used for this work, although there are still German Shepherds being trained. In 2013, about 15% of the dogs trained by Guide Dogs of America were German Shepherds, while
6840-411: The United States, the German Shepherd was responsible for the most bites severe enough to require hospital treatment. While an Australian report from 1999 provides statistics showing that German Shepherds are the breed third most likely to attack a person in some Australian locales, once their popularity is taken into account, the percentages of attacks by German Shepherds drops to 38th. According to
6954-513: The United States. As of 2016 , the German Shepherd is the second most popular breed in the US. It is typically among the most frequently registered breeds in other countries. It was the third-most registered breed by the American Kennel Club in 2020, and seventh-most registered breed by The Kennel Club in the United Kingdom in 2016. Many common ailments of the German Shepherd are a result of
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#17330856332717068-493: The animal, while other states, such as Arizona, do not have any laws about owning a wolfdog hybrid. States may or may not create their own laws regarding the issue of wolfdog hybrids. Chromosome This is an accepted version of this page A chromosome is a package of DNA containing part or all of the genetic material of an organism . In most chromosomes, the very long thin DNA fibers are coated with nucleosome -forming packaging proteins ; in eukaryotic cells,
7182-499: The appearance of the wolfdog will most likely contain a narrower chest, longer legs, and sharper teeth because it inherited more traits from the wolf parent. People wanting to improve domestic dogs or create an exotic pet may breed domestic dogs to wolves. Gray wolves have been crossed with dogs that have a wolf-like appearance, such as German Shepherds to form the Czechoslovakian Wolfdog . The breeding of wolf–dog crosses
7296-512: The area. Although hybridization has not been detected elsewhere, scientists are concerned that it could pose a threat to the wolf population's genetic integrity, resulting in outbreeding depression or a reduction in fitness, though this does not appear to have taken place. The African gold wolf is known to hybridize with both domestic dogs and Ethiopian wolves, as well as Golden jackals. Although hybridization between wolves and golden jackals has never been observed, evidence of such occurrences
7410-598: The boundaries to keep sheep from trespassing and damaging the crops. In Germany and other places these skills are tested in utility dog trials also known as Herdengebrauchshund (HGH) herding utility dog trials. One Mexican German Shepherd, Zuyaqui , was dissected and his body put on display at the Sedena 's " Narco Museum " in Mexico. He is regarded to be the dog who has captured the most drugs in Mexican police and military history. When
7524-415: The cell may undergo mitotic catastrophe . This will usually cause the cell to initiate apoptosis , leading to its own death , but the process is occasionally hampered by cell mutations that result in the progression of cancer . The term 'chromosome' is sometimes used in a wider sense to refer to the individualized portions of chromatin in cells, which may or may not be visible under light microscopy. In
7638-423: The cell's nucleus. Each chromosome has one centromere , with one or two arms projecting from the centromere, although, under most circumstances, these arms are not visible as such. In addition, most eukaryotes have a small circular mitochondrial genome , and some eukaryotes may have additional small circular or linear cytoplasmic chromosomes. In the nuclear chromosomes of eukaryotes, the uncondensed DNA exists in
7752-417: The center of the cell in their condensed form. Before this stage occurs, each chromosome is duplicated ( S phase ), and the two copies are joined by a centromere —resulting in either an X-shaped structure if the centromere is located equatorially, or a two-armed structure if the centromere is located distally; the joined copies are called ' sister chromatids '. During metaphase, the duplicated structure (called
7866-507: The closest living relatives to modern humans, have 48 chromosomes as do the other great apes : in humans two chromosomes fused to form chromosome 2 . Chromosomal aberrations are disruptions in the normal chromosomal content of a cell. They can cause genetic conditions in humans, such as Down syndrome , although most aberrations have little to no effect. Some chromosome abnormalities do not cause disease in carriers, such as translocations , or chromosomal inversions , although they may lead to
7980-406: The compact metaphase chromosomes of mitotic cells. The DNA is thus condensed about ten-thousand-fold. The chromosome scaffold , which is made of proteins such as condensin , TOP2A and KIF4 , plays an important role in holding the chromatin into compact chromosomes. Loops of thirty-nanometer structure further condense with scaffold into higher order structures. This highly compact form makes
8094-470: The contention that the red wolf is a subspecies of the gray wolf. However, recent genetic and morphological evidence suggests that the red wolf is a unique taxon. Wilson et al. (2000) report that gray wolves ( Canis lupus lycaon ) in southern Ontario appear genetically very similar to the red wolf and that these two canids may be subspecies of one another and not a subspecies of gray wolf. Wilson et al. (2000) propose that red wolves and C. lupus lycaon should be
8208-481: The coyote population would have acquired more and more dog-like traits. Hybridization between gray wolves and coyotes has long been recognized both in the wild and in captivity. In an evolutionary biology research conducted by a team of researchers in the Uppsala University, analysis of control region haplotypes of the mitochondrial DNA and sex chromosomes from Mexican wolves, a critically endangered subspecies of
8322-560: The disorder. This condition has been observed in breeds that were crossed with German Shepherd dogs such as the Karelian Bear dog , Saarloos Wolfhound , and the Czechoslovakian Wolfdog . Pituitary dwarfism in other dog breeds (excluding those with German Shepherd ancestry) is extremely rare. Unlike humans where the POU1F1 and PROP1 genes are responsible for the defect a mutation in the LHX3 gene
8436-424: The dog he changed his name to Horand von Grafrath and von Stephanitz founded the Verein für Deutsche Schäferhunde (Society for German Shepherd Dogs). Horand was declared to be the first German Shepherd Dog, and was the first dog added to the society's breed register. In just a few decades of the Verein für Deutsche Schäferhunde 's establishment, the breed became one of the world's most popular and numerous,
8550-479: The formal breed name of the American Kennel Club and was removed in 2010. German Shepherds are medium to large-sized dogs. The breed standard height at the withers is 60–65 cm (24–26 in) for males, and 55–60 cm (22–24 in) for females. German Shepherds can reach sprinting speeds of up to 30 miles per hour. Shepherds are longer than they are tall, with an ideal proportion of 10 to 8 + 1 ⁄ 2 . The AKC official breed standard does not set
8664-473: The genus Burkholderia carry one, two, or three chromosomes. Prokaryotic chromosomes have less sequence-based structure than eukaryotes. Bacteria typically have a one-point (the origin of replication ) from which replication starts, whereas some archaea contain multiple replication origins. The genes in prokaryotes are often organized in operons and do not usually contain introns , unlike eukaryotes. Prokaryotes do not possess nuclei. Instead, their DNA
8778-411: The gray wolf once nearly driven to extinction in the wild, confirmed the presence of coyote markers in some of the wolves. The study suggests that at some point in time, female coyotes managed to mate with some of the male wolves of the remnant wild Mexican wolf populations. Analysis on the haplotype of some coyotes from Texas also detected the presence of male wolf introgression, such as Y chromosomes from
8892-567: The gray wolves in the southern coyotes. In one cryptozoological investigation on a corpse of what was initially labelled as a chupacabra , examinations conducted by the UC Davis team and the Texas State University concluded based on the sex chromosomes that the male animal was in fact another coyote and wolf hybrid sired by a male Mexican wolf. DNA analysis consistently shows that all existing red wolves carry coyote genes. This has caused
9006-563: The inbreeding practised early in the breed's life. One such common ailment is hip and elbow dysplasia which may cause the dog to experience pain later on in life and may cause arthritis . A study conducted by the University of Zurich found that 45% of the police working dogs were affected by degenerative spinal stenosis, although a small sample size was used. The Orthopedic Foundation for Animals found that 19.1% of German Shepherd are affected by hip dysplasia. Multiple studies have found
9120-583: The independent work of Boveri and Sutton (both around 1902) by naming the chromosome theory of inheritance the ' Boveri–Sutton chromosome theory ' (sometimes known as the 'Sutton–Boveri chromosome theory'). Ernst Mayr remarks that the theory was hotly contested by some famous geneticists, including William Bateson , Wilhelm Johannsen , Richard Goldschmidt and T.H. Morgan , all of a rather dogmatic mindset. Eventually, absolute proof came from chromosome maps in Morgan's own laboratory. The number of human chromosomes
9234-509: The individual chromosomes visible, and they form the classic four-arm structure, a pair of sister chromatids attached to each other at the centromere . The shorter arms are called p arms (from the French petit , small) and the longer arms are called q arms ( q follows p in the Latin alphabet; q-g "grande"; alternatively it is sometimes said q is short for queue meaning tail in French ). This
9348-486: The issue of soundness in the show strain of the breed. Some show strains have been bred with an extremely roached topline (back) that causes poor gait in the hind legs. The issue was raised in the BBC documentary, Pedigree Dogs Exposed , which said that critics of the breed describe it as "half dog, half frog". An orthopaedic vet remarked on footage of dogs in a show ring that they were "not normal". The Kennel Club's position
9462-450: The life expectancy of the German Shepherd to be lower than that of the overall life expectancy found in the study: a 2024 UK study found a life expectancy of 11.3 years, compared to 12 years for crossbreeds and 12.7 years for purebreds; a 2022 UK study using veterinary records found a life expectancy of 10.16 years compared to 11.23 overall and 11.82 for crossbreeds; in Italy a 2024 study found
9576-494: The matching chromosomes of father and mother can exchange small parts of themselves ( crossover ) and thus create new chromosomes that are not inherited solely from either parent. When a male and a female gamete merge during fertilization , a new diploid organism is formed. Some animal and plant species are polyploid [Xn], having more than two sets of homologous chromosomes . Important crops such as tobacco or wheat are often polyploid, compared to their ancestral species. Wheat has
9690-429: The membranes (and the attached DNA). Prokaryotic chromosomes and plasmids are, like eukaryotic DNA, generally supercoiled . The DNA must first be released into its relaxed state for access for transcription , regulation, and replication . Each eukaryotic chromosome consists of a long linear DNA molecule associated with proteins , forming a compact complex of proteins and DNA called chromatin . Chromatin contains
9804-456: The most important of these proteins are the histones . Aided by chaperone proteins , the histones bind to and condense the DNA molecule to maintain its integrity. These eukaryotic chromosomes display a complex three-dimensional structure that has a significant role in transcriptional regulation . Normally, chromosomes are visible under a light microscope only during the metaphase of cell division , where all chromosomes are aligned in
9918-524: The name was adopted for use in the stud-book ; however, at the end of the First World War , it was believed that the inclusion of the word "German" would harm the breed's popularity, due to the anti-German sentiment of the era. The breed was officially renamed by the UK Kennel Club to "Alsatian Wolf Dog", after the French region of Alsace bordering Germany. Eventually, the appendage "wolf dog"
10032-501: The original breed. The Shiloh Shepherd is a variety of the German Shepherd bred in the United States. It was developed in the 1970s and 1980s to correct behavioural and conformational issues that have been bred into modern German Shepherds, and was bred for its large size, length of back, temperament and soundness of hips. It has been recognised since 1990 by the American Rare Breed Association . The White Shepherd
10146-444: The perfect working dog. In 1899, von Stephanitz was attending a dog show when he was shown a dog named Hektor Linksrhein. Hektor was the product of few generations of selective breeding and completely fulfilled what von Stephanitz believed a working dog should be. He was pleased with the strength of the dog and was so taken by the animal's intelligence, loyalty, and beauty, that he purchased him immediately. After purchasing
10260-722: The presence of enemies or of booby traps or other hazards. German Shepherds have also been trained by military groups to parachute from aircraft or as anti-tank weapons . They were used in World War II as messenger dogs, rescue dogs and personal guard dogs. The German Shepherd is one of the most widely used breeds in a wide variety of scent-work roles. These include search and rescue, cadaver searching , narcotics detection, explosives detection , accelerant detection and mine detection dog, among others. They are suited for these lines of work because of their keen sense of smell and their ability to work regardless of distractions. At one time
10374-547: The rediscovery at the start of the 1900s of Gregor Mendel 's earlier experimental work, Boveri identified the connection between the rules of inheritance and the behaviour of the chromosomes. Two generations of American cytologists were influenced by Boveri: Edmund Beecher Wilson , Nettie Stevens , Walter Sutton and Theophilus Painter (Wilson, Stevens, and Painter actually worked with him). In his famous textbook, The Cell in Development and Heredity , Wilson linked together
10488-489: The remainder are Labrador Retrievers and Golden Retrievers. The Guide Dogs for the Blind Association in the United Kingdom trains some German Shepherds, while the comparable organisation in the US only trains Labrador Retrievers, Golden Retrievers and crosses between these breeds. German Shepherds are still used for herding and tending sheep grazing in meadows next to gardens and crop fields. They are expected to patrol
10602-477: The result of poor breeding, which caused the breed to decline in popularity during the late 1920s. Popularity increased again after Sieger Pfeffer von Bern became the 1937 and 1938 Grand Victor in American Kennel club dog shows, only to have another decline at the conclusion of World War II, due to anti-German sentiment. Popularity increased gradually until 1993, when they became the third most popular breed in
10716-486: The risk of aneuploid spermatozoa. In particular, risk of aneuploidy is increased by tobacco smoking, and occupational exposure to benzene, insecticides, and perfluorinated compounds. Increased aneuploidy is often associated with increased DNA damage in spermatozoa. The number of chromosomes in eukaryotes is highly variable. It is possible for chromosomes to fuse or break and thus evolve into novel karyotypes. Chromosomes can also be fused artificially. For example, when
10830-438: The same in all body cells. However, asexual species can be either haploid or diploid. Sexually reproducing species have somatic cells (body cells) that are diploid [2n], having two sets of chromosomes (23 pairs in humans), one set from the mother and one from the father. Gametes (reproductive cells) are haploid [n], having one set of chromosomes. Gametes are produced by meiosis of a diploid germline cell, during which
10944-559: The same time, the awareness of sheepdogs as a versatile, intelligent class of canine began to rise. Max von Stephanitz , an ex-cavalry captain and former student of the Berlin Veterinary College, was an ex-member of the Phylax Society who firmly believed dogs should be bred for working. He admired the intelligence, strength and ability of Germany's native sheepdogs, but could not find any one single breed that satisfied him as
11058-428: The same way as purebred wolves. In the United States, legislation differs greatly from state to state. In New York, the law does not allow an individual to house or own a dog hybrid of any kind, even if there is a low percentage of wolf genes in the hybrid. States such as Indiana and Arkansas allow the ownership of hybrid animals, but they regulate it strictly with health records, immunization records, and registration of
11172-594: The set of chromosomes arranged, autosomes in order of length, and sex chromosomes (here X/Y) at the end. Like many sexually reproducing species, humans have special gonosomes (sex chromosomes, in contrast to autosomes ). These are XX in females and XY in males. Investigation into the human karyotype took many years to settle the most basic question: How many chromosomes does a normal diploid human cell contain? In 1912, Hans von Winiwarter reported 47 chromosomes in spermatogonia and 48 in oogonia , concluding an XX/XO sex determination mechanism . In 1922, Painter
11286-449: The traits in dogs that the society should promote; some members believed dogs should be bred solely for working purposes, while others believed dogs should be bred also for appearance. While unsuccessful in their goal, the Phylax Society had inspired people to pursue standardising dog breeds independently. With the rise of large, industrialised cities in Germany, the predator population began to decline, rendering sheepdogs unnecessary. At
11400-459: The vast majority of the DNA in an organism, but a small amount inherited maternally can be found in the mitochondria . It is present in most cells , with a few exceptions, for example, red blood cells . Histones are responsible for the first and most basic unit of chromosome organization, the nucleosome . Eukaryotes ( cells with nuclei such as those found in plants, fungi, and animals) possess multiple large linear chromosomes contained in
11514-620: The wild dingo population, where they breed with pure dingoes. The Australian Cattle Dog and Australian Stumpy Tail Cattle Dog breeds are known to have been created by crossing domesticated herding dogs, like the Collie , with the dingo. Coydogs (the offspring of a male coyote and a female domestic dog) are naturally occurring red or blond color variations of the coyote and feral dogs . The breeding cycles of domestic dogs and coyotes are not synchronized and this makes interbreeding uncommon. If interbreeding had been common, each successive generation of
11628-412: The wolf to the domestic dog becomes even larger when a mix of the two animals is created. Wolfdogs do not have one common description of their appearance because it varies from one breeding cycle to the next. It differs from cycle to cycle because the number of wolf genes inherited in the animal differs greatly and is recorded in a percentage form. The general layout for describing the percentage of wolfdogs
11742-473: The wolf, and became very fashionable during the Nazi era. Adolf Hitler acquired a German Shepherd named "Prinz" in 1921, during his years of poverty, but he had been forced to lodge the dog elsewhere. However, she managed to escape and return to him. Hitler, who adored the loyalty and obedience of the dog, thereafter developed a great liking for the breed. Hitler kept several more of the breed, including Blondi , who
11856-433: The wolf-like canids, have fewer chromosomes and cannot hybridize with them. (recently proven, partly incorrect, see pampas fox with dog below) For instance, the red fox has 34 metacentric chromosomes and from 0 to 8 small B chromosomes, the raccoon dog has 42 chromosomes, and the fennec fox has 64 chromosomes. The domestic dog ( Canis familiaris ) is a domesticated species of the gray wolf ( Canis lupus ), along with
11970-521: The world. The dingo is closely related to the New Guinea singing dog though recent DNA sequencing of a 'pure' wild dingo from South Australia suggests that the dingo is 'intermediate' between wolves and domestic dogs. This would make dingos a subspecies of wolf and so interbreeding between dingos and domestic dogs is also not a hybridization in the same sense as an interbreeding between different species of Canidae . Some dingo hybrids are accepted back into
12084-420: Was Hektor von Schwaben. Hektor was inbred with another of Horand's offspring and produced Heinz von Starkenburg, Beowulf, and Pilot, who later sired a total of 84 pups, mostly through being inbred with Hektor's other offspring. This inbreeding was deemed necessary in order to fix the traits being sought in the breed. Beowulf's progeny also were inbred and it is from these pups that all German Shepherds draw
12198-506: Was among several dogs in the ' Führerbunker ' during the Battle of Berlin at the end of the Second World War. Dogs played a role in Nazi propaganda by portraying Hitler as an animal lover. Preparing for his suicide , Hitler ordered Dr. Werner Haase to test a cyanide capsule on Blondi, and the dog died as a result. Erna Flegel , a nurse who worked at the emergency casualty station in
12312-478: Was coined by the German anatomist Heinrich Wilhelm Waldeyer , referring to the term ' chromatin ', which was introduced by Walther Flemming . Some of the early karyological terms have become outdated. For example, 'chromatin' (Flemming 1880) and 'chromosom' (Waldeyer 1888) both ascribe color to a non-colored state. Otto Bütschli was the first scientist to recognize the structures now known as chromosomes. In
12426-595: Was discovered through mtDNA analysis on jackals in Bulgaria. Although there is no genetic evidence of gray wolf-jackal hybridization in the Caucasus Mountains, there have been cases where otherwise genetically pure golden jackals have displayed remarkably gray wolf-like phenotypes , to the point of being mistaken for wolves by trained biologists. Several years ago, I saw confined in the Zoological Gardens of London
12540-473: Was dropped, after numerous campaigns by breeders who were worried that becoming known as a wolf-dog hybrid would affect the breed's popularity and legality. The name Alsatian remained for five decades, until 1977, when successful campaigns by dog enthusiasts pressured the British kennel clubs to allow the breed to be registered again as German Shepherds. The word "Alsatian" once appeared in parentheses as part of
12654-456: Was found in Vacaria City , Rio Grande do Sul , Brazil. DNA analysis indicates that the canid was a hybrid between a pampas fox and a domestic dog. Dubbed a ' Dogxim ' or 'graxorra', this finding is the first documented case of hybridisation detected between these two species. Dog hybrids kept as pets are prohibited in certain jurisdictions, or are classed as wild animals and must be housed in
12768-440: Was not certain whether the diploid number of man is 46 or 48, at first favouring 46. He revised his opinion later from 46 to 48, and he correctly insisted on humans having an XX/XY system. New techniques were needed to definitively solve the problem: It took until 1954 before the human diploid number was confirmed as 46. Considering the techniques of Winiwarter and Painter, their results were quite remarkable. Chimpanzees ,
12882-544: Was published by Painter in 1923. By inspection through a microscope, he counted 24 pairs of chromosomes, giving 48 in total. His error was copied by others, and it was not until 1956 that the true number (46) was determined by Indonesian-born cytogeneticist Joe Hin Tjio . The prokaryotes – bacteria and archaea – typically have a single circular chromosome . The chromosomes of most bacteria (also called genophores ), can range in size from only 130,000 base pairs in
12996-603: Was recognised that the breed had the necessary skills for herding sheep, such as intelligence, speed, strength and keen senses of smell. The results were dogs that were able to do such things, but that differed significantly, both in appearance and ability, from one locality to another. To combat these differences, the Phylax Society was formed in 1891 with the intention of creating standardised development plans for native dog breeds in Germany. The society disbanded after only three years due to ongoing internal conflicts regarding
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