The origin of domestic dogs is unclear. The domestic dog is a member of the genus Canis , which is part of wolf-like canids, and is the most abundant terrestrial carnivore. The closest relatives of the closest dog are the remaining gray wolves, and there is no evidence of other dogs contributing to their genetic lineage. The still gray dog ​​and gray wolf is a taxi brother, since the modern wolf is not closely related to the first tamed wolf. Archaeological records and genetic analysis show the remains of a Bonn-Oberkassel dog buried next to humans 14,200 years ago became the first undisputed dog, with remnants of disputes that occurred 36,000 years ago. These dates imply that the earliest dogs appeared at the time of human hunter-gatherers and not farmers. The dog is the first species to be domesticated.
Where the genetic differences of dogs and wolves occur is still controversial, with the most plausible proposals covering Western Europe, Central Asia and East Asia. This has been made more complicated by recent proposals that fit the available evidence, namely that the initial wolf population is divided into Eastern and Western Eurasian groups; this, before becoming extinct, was tamed independently into two different dog populations between 14,000 and 6,400 years ago. The West Eurasian dog population is partially and gradually replaced by an East Asian dog introduced by humans at least 6,400 years ago.
Video Origin of the domestic dog
Canid and human evolution
Six million years ago, towards the end of the Miocene era, the Earth's climate gradually cooled and this would lead to the glaciers of the Pliocene and the Pleistocene - the Ice Age. In many areas, forests and savannas are replaced with grasslands or meadows and only creatures that can adapt that will survive. On the opposite side of the planet, two very different lineages will adapt to this change and their evolution will produce two species that will be the most distributed mammals. In southern North America, small forest foxes grow larger and become better adapted for running, and at the end of the first genus Miocene Canis have appeared - the ancestors of coyotes, wolves and domestic dogs. In eastern Africa, there was division among the great primates. Some will remain in the trees, while others will descend from trees, learn to walk upright, develop larger brains, and in more open countries learn to avoid predators when they become predators themselves. The two lineages will eventually meet on the Eurasian continent.
They are the individual animals and the people involved, from our perspective, in biological and cultural processes that involve connecting not only their lives but the evolutionary fate of their heirs in a way, we must assume, they will never imagine it. - Mark Derr
Maps Origin of the domestic dog
Evolution of the dog
Evolution (from Latin evolutio : "unrolled") is defined by English naturalist, geologist and biologist Charles Darwin as biological offspring with modification. Evolution ultimately divides the ancestral population into a new species that can not, or will not, interbreed.
Domestic dogs are the first and only major domesticized carnivorous species. Over the past 200 years, dogs have undergone rapid phenotypic changes and formed into modern dog breeds today due to man-made artificial selection. These breeds can vary in size and weight from 0.46 kg (1.0 Â £) cup of poodle to a gigantic mastiff weighing 90 kg (200 pounds). The skull, body, and limb proportions vary significantly among breeds, with dogs exhibiting more phenotypic diversity than can be found in all carnivorous sequences. Some breeds exhibit extraordinary skills in herding, picking, detecting aromas, and preserving, which shows the functional diversity and behavior of dogs. There is great progress in understanding the genes that give rise to the phenotypic nature of dogs. The first dogs are certainly wolves, but phenotypic changes that coincide with the dog-wolf genetic differences are unknown.
The cause and context of dog domestication is unknown. Taking the time and place for domestication can help illustrate the conditions that bring up large carnivorous associations with hunter-gatherers. All other domestication events occur during or after agricultural development, which is approximately 10,000 years before now (YBP). The dog's previous relationship with humans may have allowed the dog to have a major influence on the course of early human history and the development of civilization. However, time, geographic location, and ecological conditions that lead to dog domestication are not approved.
Genetic studies show that the gray wolf is the closest relative of the dog, with no evidence of any other species of dog contributing. Trying to reconstruct the genealogy of dogs through phylogenetic analysis of the DNA sequences of dogs and modern wolves has given conflicting results for several reasons. First, research shows that the extinct Late Pleistocene wolf is the closest ancestor of the dog, with modern wolves not being the direct ancestors of dogs. Second, the genetic differences between dogs and modern wolves occur over a short period of time, so the divergence time is difficult to date (referred to as incomplete line sorting). This is further complicated by the cross-breeding that has occurred between dogs and wolves since domestication (referred to as the post-domestication gene flow). Finally, there are only tens of thousands of generations of dogs since domestication, so the number of mutations between dogs and wolves is minimal and this makes the domestication time to be difficult to date.
Genesis, archeology, and morphology Genetics, archeology, and morphology
Domestic dogs are the most abundant large carnivores. When and where dogs were first domesticated have been taxing geneticists for the last 20 years and archaeologists for many decades longer. Identifying the earliest dogs is difficult because key morphological characters used by zooarkeologists to distinguish domestic dogs from their wild wolf ancestors (tooth size and position, dental pathology, and size and proportion of skull and postkranial elements) have not been improved during the early phase of the domestication process. The range of natural variation among these characters that may have existed in the population of ancient wolves, and the time required for these traits to appear in dogs, is unknown.
However, recent studies based on genetics put forward five generalizations about dogs.
- Over the past millions of years, many shapes like wolves have appeared but the turnover is high, and modern wolves are not the ancestors of dog breeds. Although research has shown that dogs and wolves are genetically close relatives, then phylogenetic analysis strongly supports the hypothesis that dogs form monophyletic clones that are Eurasian wolves, and these together form a sister clade to North American wolves. This indicates that the remaining wolf populations for dogs have not been found, and it is suspected that wolves soon ancestors for extinct dogs. The dog is not a separate species for wolves.
- The study proposes the timing of deviation of dogs from wolves' ancestors to approximately 27,000 YBP, with the latest proposed 36,900-41,500 YBP followed by domestication occurring between 20,000-40,000 YBP.
- The dog was the first pet species and appeared more than 15,000 years before today (YBP). These dogs were established throughout Eurasia before the end of the late Pleistocene era, long before the cultivation and domestication of other animals around 10,000 YBP, indicating that dogs were tamed by hunter-gatherers and not early farmers. Studies supporting two population congestions have occurred in dog lineages, one due to early domestication and one due to the formation of dog breeds.
- Dogs show ancient and modern lineages. Ancient lineages are most prevalent in Asia but at least in Europe because the development of modern-day modern dog breeds is used somewhat from ancient lineages. All dog populations (breeding, village, and wild) show some evidence of genetic mixing between modern and ancient dogs. Some of the ancient dog populations that once occupied Europe and the New World ceased to exist. This implies that some of the ancient dog populations are completely replaced and others are mixed over a long period of time.
- There is a mixture between dog and regional wolf populations except in the Tibetan Plateau and the New World wolves. This mixing has occurred throughout history and as the dog spreads its wings across the landscape. There are some dog populations that show the final mixing with wolves.
The extinction of the wolf which is the direct ancestor of the dog, and the continued mixing between different dog and wolf populations for at least the last 10,000 years, has obscured the genetic signatures and attempts of confusing researchers in determining the origin of dogs. The alternative proposal is that during the ecological upheaval of the Late Pleistocene, all remaining members of the diminishing lineage join the human.
The time of divergence
Paleoecology
During the last Ice Age, the last peak is known as the Last Glacial Maximum when a large field of giant stretches from Spain eastward across Eurasia and through Bering's land bridge to Alaska and Yukon. Continental Europe is much colder and drier than it is now, with the polar desert to the north and the rest of the meadow or tundra. Forests and forests are virtually absent except for remote pockets in the mountains of southern Europe. The Late Pleistocene is characterized by a series of severe and rapid climate oscillations with regional temperature changes of up to 16 ° C, which have been correlated with the extinction of the Pleistocene megafauna. There is no evidence of megafaunal extinction at the elevation of the Last Glacial Maximum, indicating that the increase in cold and glaciation is not a factor. Events appear to have caused rapid replacement of one species by another species in the same genus, or one population with another in the same species, across a large area. Because some species are extinct, so are the predators who depend on them. The ancestors of modern humans first arrived in Europe, with their bodies dated from 43,000 to 45,000 years old in Italy and in England.
- See more: Current Paleoecology
Ancestor possibilities
During the Last Glacial Maximum, there are two types of wolves. The cold northern part of Holarctic is stretched by a large, powerful, wolf ecomorph that specifically preys on megafauna. Another leaner form lives in the warmer south at the protection of the glaciation. As the planet warms up and the Glacial Maximum End comes to a close, the entire megafauna species become extinct along with their predators, leaving more gracile wolves to dominate Holarctic. The more gracile wolf is the ancestor of the modern gray wolf, who is the sister of the dog but not its ancestor because it shows a genetic link closer to the now extinct megafaun wolf.
- See more: Two wolf haplogroups
Evolution divergence
The expected date for the evolutionary differences of the domestic lineage of the wild does not necessarily indicate the beginning of the domestication process but it gives the upper limit. Domestic horses drift from the lineage causing modern Przewalski horse is estimated at 45,000 YBP but archaeological records show 5,500 YBP. The variance may be because the modern wild population is not a direct ancestor of the domestic, or the impact of disunity due to climate, topography, or other environmental changes. The time of divergence does not imply domestication during this particular period. Some researchers propose that "dogs are dogs before being domesticated" and that the ancestors of Canis familiaris are a wild Canis familiaris, who have deviated from common ancestors along with gray wolves.
Early mitochondrial DNA analysis showed that if the dog had descended from modern gray wolves then the difference would be 135,000 YBP. Two later studies using whole genome sequencing showed a divergence time of 32,000 YBP or 11,000-16,000 YBP, with assumed mutation rates "the dominant source of uncertainty in determining the origin of dogs."
- See more: Mutation timing issue
In 2015, a study was conducted on partial ribs (designated as Taimyr-1) found near the Balakhnaya Bolshaya River on the Taymyr Peninsula, North Asia Arctic, the AMS radiocarbon dated 34,900 YBP. The samples gave the first genome design of the Pleistocene carnivore nucleus and the sequence was identified as belonging to Canis lupus . The sequence shows that the Taimyr-1 lineage is separated from wolves and modern dogs. Using the radiocarbon dates of Taimyr-1 specimens in addition to their genome sequence compared with modern wolves, direct estimates of mutation rates in dogs and wolves can be performed to calculate the time of divergence. This study shows that the population of Taimyr-1, the gray wolf and dog deviate from the now-extinct ancestor before the summit of the last Ultimate Escape 27,000-40,000 years ago. Such early deviations are consistent with some paleontological reports of dogs such as dated up to 36,000 YBP, as well as evidence that pet dogs are likely accompanied by early invaders to America. This study proposes that the separation time of dogs and wolves does not necessarily coincide with selective breeding by humans.
In 2017, a study compared nuclear genome sequences of Neolithic dog specimens with sequences of more than 5,000 dogs and wolves. This Neolithic dog specimen includes dog samples from the Early Neolithic site in Herxheim, Germany on 7,000 YBP, one from the Neolithic Site of the End of the Kirschbaum Cave (Sakura Tree) near Forchheim, Germany dated 4,700 YBP, and one found in the Neolithic section of the End of the tomb in Newgrange, Ireland on 4,800 YBP. The study calculated the rate of mutation for 7,000 Neolithic YBP dogs and found that it matched the mutation rate of the Taimyr-1 specimen, and noted that this also matched the rate of mutations for Newgrange dogs that had been calculated in previous studies. Using a specimen of 7,000 YBP and this rate of mutation, the dog wolf uniformity time is estimated to have occurred 36,900-41,500 YBP and this is consistent with the time found with Taimyr-1 specimens in previous studies.
In 2018, a study examined the lineage of male y-chromosome canine teeth, including ancient fossils of Herxheim, Kirschbaum, and Newgrange dogs. The study identified six major yDNA haplogroups, two of which included the majority of modern dogs. Newgrange dogs fall into the most common of these haplogroups. The two ancient German dogs fell into the haplogroup commonly found among dogs from the Middle East and Asia, with the Kirschbaum dog sharing the same male lineage as the remaining Indian wolves. The study concludes that at least 2 different male haplogroups exist in ancient Europe, and that the male dog lineage deviates from its closest ancestor along with a gray wolf sometimes between 68,000-151,000 YBP.
Place of divergence
Where the genetic differences of dogs and wolves occur is still controversial, with the most plausible proposals covering Western Europe, Central Asia, and East Asia. This has been made more complicated by recent proposals that fit the existing evidence, namely that the early wolf population split into East and West Eurasian wolves, was then tamed independently before it became extinct into two different dog populations between 14,000-6,400 years old. then, and then the Western Eurasian dog population is partially and gradually replaced by an East Asian dog brought by humans at least 6,400 years ago.
Using modern DNA
Europe In 2007, a study of mDNA sequences of mothers from dogs and wolves showed that their haplotypes were resolved into four clad monophyletic (clusters that included their ancestors), in which two clades showed a strong relationship between dogs and dogs. the European wolf.
Southeast Asia: In 2009, a study of the mother's mitochondrial genome showed origin in Southeast Asia south of the Yangtze River because more haplogroup dogs were found there. The DNA sequence of the Paternal Y-chromosome indicates the south-western part of Southeast Asia that lies south of the Yangtze River (comprising Southeast Asia and Yunnan and Guangxi China provinces) because of the greater diversity of haplogroup yDNAs found within the region. The criticism of this proposal is that no wolves are found in this region and the earliest archaeological evidence about a dog comes from only 4,700 YBP.
Middle East: In 2010, a study using single nucleotide polymorphisms showed that dogs originated in the Middle East because of sharing larger haplotypes between dogs and Middle Eastern gray wolves; others may have significant mixing between several regional and regional wolves. In 2011, a study found that there was a wolf dog hybridization and not an independent domestication.
East Asia: In 2002, a study of maternal mDNA showed that the dog deviated from its ancestors in East Asia because more mDNA haplotypes were found there than in other parts of the world, but this was denied by dogs villages in Africa also show the same diversity of haplotypes. By 2015, the whole genome analysis of modern dog and wolf sequences concludes that based on the genetic diversity of Eastern Asian dogs today, the dog is from southern Southeast Asia, followed by migration of a subset of 15,000 YBP ancestral dogs to the Middle East, Africa and Europe and reach Europe 10,000 YBP. Later, one of these lineages migrated back to northern China and mixed with Asian endemic lineages before migrating to America. The criticism of this proposal is that no dogs continue to date outside 12,000 YBP in the region but date for 14,000 YBP in Western Europe, but it is accepted that archaeological studies in the Far East are generally lagging behind them in Europe.
Central Asia: By 2015, a study of 85,805 autosomal genetic markers, maternal mitochondrial genes and Y chromosome dad diversity in 4,676 race dogs from 161 breeds and 549 village dogs from 38 countries. Some dog populations in Neotropics and the South Pacific are almost entirely derived from European stocks, and other regions show a clear mixing between indigenous dogs and European dogs. The population of native dogs in Vietnam, India, and Egypt showed minimal evidence of European mixing, and exhibit indicators consistent with Central Asian domestication, followed by population expansion in East Asia. This study can not rule out the possibility that dogs are tamed elsewhere and then arrive at and diversify from Central Asia. The study of existing dogs can not exclude the possibility of earlier domestic events that were later dead or overwhelmed by more modern populations.
There is no agreement on using modern DNA: By 2016, genetic studies of all wolves and dogs conclude that mixing has puzzled the ability to make inferences about where dog domestication is. Previous studies based on single nucleotide polymorphisms, wide-genome similarities with Chinese wolves, and lower relative disequilibrium may reflect regional mixing between dogs with wolves and gene flow between dog populations, with genetically different breeds of dogs likely to retain more wolf ancestors in their genome. This study proposes that primitive DNA analysis may be a better approach.
Using ancient DNA
In his book of 1868 on Variation under Domestication , Charles Darwin assessed the argument for the singular or double origin of the dog, and notes the de Blainville paleontological study proposing that dogs be descended from extinct species. In 1934, a leading paleontologist pointed out that the ancestors of the dog lineage may have become extinct Canis variabilis . In 1950, the Japanese prehistoric dog's morphology research compared to the remaining wolves concluded: "Therefore the type of living wolf has nothing to do with the ancestral form of prehistoric dog breeds." In 1999, a study stressed that while molecular genetic data appears to support the dog's origin from wolves, dogs may originate from an extinct cannon species, whose closest relative is a wolf. Dog breeds may have contributed from the ghost population. The advent of rapid and inexpensive DNA sequencing technology has made it possible to significantly increase the power of genetic data drawn from the genomes of modern and ancient domestic dogs. Attention now turns to research based on ancient DNA from fossil canids.
Europe: In 2013, a study analyzed the complete and partial sequence of mitochondrial genomes from 18 fossils originating from 1,000 to 36,000 YBP from Old and New Worlds, and compared them with complete mitochondrial genomes sequences from modern. wolves and dogs. Phylogenetic analysis showed that mAPNA modern dog haplotypes became four clad monophyletic with strong statistical support, and this has been designated by researchers as A-D clades. Based on the specimens used in this study, clade A included 64% of dog samples and this is the brother of the Yamps 14,500 wolf sequence from the Kessleroch cave near Thayngen in the Swiss canton of Schaffhausen with the latest common ancestor estimated at 32,100 YBP. This group of dogs is compatible with three pre-Columbian New World dog fossils dating between 1,000 and 8,500 YBP, supporting the hypothesis that pre-Columbian dogs in the New World have ancestors with modern dogs and are likely to arrive with the first humans to New World. Clade B includes 22% of the order of dogs and is associated with the modern wolves of Sweden and Ukraine, with a common ancestor recently estimated at 9,200 YBP. However, this relationship may represent the mitochondrial genetic introgression of the wolf because dogs are domesticated today. Clade C includes 12% of dog samples and this is the brother of two ancient dogs from the Bonn-Oberkassel (14,700 YBP) cave and Kartstein's cave (12,500 YBP) near Mechernich in Germany, with a recent common ancestor estimated at 16,000-24,000 YBP. Clade D contains the sequence of 2 Scandinavian breeds (Jamthund, Norwegian Elkhound) and is the brother of 14,500 YBP wolf sequences as well as from the Kesserloch cave, with a recent common ancestor estimated at 18,300 YBP. The branches are phylogenetically rooted in the same order as the "Altai dog" (not the direct ancestor). Data from this study show European origin for dogs estimated at 18,800-32,100 years ago based on a genetic relationship of 78% of dog samples with ancient canid specimens found in Europe. The data support the hypothesis that dog domestication precedes the emergence of agriculture and begins close to the Last Glacial Maximum when hunter-gatherers prey on megafauna.
The study found that three ancient Belgian canopies (36,000 YBP "Goyet dogs" categorized as Canis species, along with Belgian 30,000 YBP and 26,000 YBP years cataloged as Canis lupus ) is formed. the ancient clade which is the most distinct group. The study found that the skulls of "Goyet dog" and "Altai dog" had characteristics such as dogs and suggested that may have represented a failed episode of domestication. If so, there may be initially more than one ancient domestication event for dogs because there are domestic pigs.
One theory is that domestication occurred during one of the five cold Heinrich events that occurred after the arrival of humanity in Western Europe 37,000, 29,000, 23,000, 16,500, and 12,000 YBP. The theory is that extreme cold weather during one of these events causes humans to change their location, adapt through distractions in their culture and change their beliefs, or adopt an innovative approach. The adoption of wolves/big dogs is an adaptation to this hostile environment.
Critics of the European proposal are that dogs in East Asia show more genetic diversity. However, dramatic differences in genetic diversity can be influenced both by ancient history and inbreeding history. A counter-commentary is that modern European breeds only appeared in the 19th century, and that throughout the history of the global dog population experienced many episodes of diversification and homogenization, with each round reducing the strength of genetic data originating from modern breeds to help infer early history.
North-East Siberian Arctic: By 2015, a study looks at the sequence of mitochondrial control regions from 13 ancient canid remains and a modern wolf from five locations in northeastern Arctic Siberia. Fourteen canines revealed nine mitochondrial haplotypes, three of which were recorded and others not previously reported. The phylum tree produced from the sequence shows that four of Siberian cans date 28,000 YBP and one Canis c.f. variabilis date 360,000 YBP is very different. The haplotype defined as S805 (28,000 YBP) from the Yana River is a mutation of the other haplotype S902 (8,000 YBP) representing Clade A from modern wolves and domestic dog breeds. Closely related to this haplotype is one found in the recently expired Japanese wolf. Some ancient haplotypes are oriented to S805, including Canis c.f. variabilis (360,000 YBP), Belgium (36,000 YBP - "Goyet dog"), Belgium (30,000 YBP), and Konsteki, Russia (22,000 YBP). Given the position of the haplotype S805 in phylogenetic trees, it has the potential to represent a direct relationship of ancestors (including Canis c.f. variabilis) to domestic dogs and modern wolf lineages. Gray wolves are considered the ancestors of domestic dogs, but their relationship to C. variabilis, and the genetic contribution of C. variabilis to dogs, is the subject of debate.
The Zhokhov Island (8,700 YBP) and Aachim (1,700 YBP) canid haplotypes fall in a domestic dog cluster, clustered with S805, and also share their haplotypes with - or one mutation from the Tibetan ( C. L chanco wolf >) and the newly extinct Japanese wolf ( C. l. hodophilax ). This may indicate that this canida maintains a mixed genetic marker with regional wolf populations. Another Haplotype designated as S504 (47,000 YBP) of Duvanny Yar appears in phylogenetic trees because it is not connected to wolves (both ancient and modern) but ancestral to dogs, and can represent a genetic source for regional dogs. Newgrange dog - two domestic events
In 2009, a study looked at two of the earliest dog skulls that have been found in Eliseevich 1 compared to similar but similar similar but similar morphologic skulls that have been found throughout Europe and concluded that the earlier specimens were "Paleolithic dogs," which were morphologically and genetically different from the wolves of the Pleistocene that lived in Europe at that time. It also includes a 36,000-year-old "Goyet dog" and a 33,000-year-old "Altai dog".
Subsequent research shows that it is possible for some primitive forms of dogs to have existed, including in Europe. The European dog population has undergone extensive turnover over the last 15,000 years that has removed the early European dog genomic marker, the genetic heritage of modern breeds has become blurred by mixing, and there is the possibility of past extinction domestication events that have been largely replaced by modern dog populations.
In 2016, a study comparing mitochondrial DNA and intact genomic sequences from a worldwide panel of modern dogs, the mDNA sequence of 59 specimens of ancient European dogs dating 14,000-3,000 YBP, and the nuclear genome sequence of dog specimens found in the Late Neolithic Tomb at Newgrange , Ireland and radiocarbon dated at 4,800 YBP. Genetic analysis of Newgrange dogs suggests that it is male, has no genetic variant associated with modern skin length or color, can not process starch as efficiently as modern dogs but is more efficient than wolves, and shows the ancestors of the wolf population. which can not be found in other dogs or wolves today. Because the taxonomic classification of "proto-dog" paleolithic dogs as dogs or wolves is controversial, they are excluded from research. The phylogenetic tree produced from the mDNA sequences finds a deep division between the Sarloos wolf and all other dogs, indicating that the offspring have recently come from the German Shepherd and the gray wolf of captives. The next largest division is between East Asian dogs and Western Eurasian dogs (Europe and the Middle East) occurring between 14,000-6,400 YBP, with Newgrange dogs clustered with Western Eurasian dogs. The northern Greenland dog and the Siberian husky are not well supported in the tree, probably indicating a mixed ancestor. (See also the wolves of the Taimyr wolves)
The Newgrange and mDNA dogs of ancient European sequences can be largely assigned to haplogroup mDNAs C and D but modern European dog sequences can be largely assigned to haplogroup A and B mDNAs, showing dog turnover in the past from somewhere other than Europe. Since this older split date of the Newgrange dog shows that the replacement was only partial. Analysis shows that most modern European dogs have encountered population constraints that can be an indicator of travel. Archaeological records show dogs still dating over 15,000 YBPs in Western Eurasia, over 12,500 YBP in Eastern Eurasia, but no more than 8,000 YBP in Central Asia. The study proposes that dogs may have been kept separately in East and West Eurasia from two genetically different and now extinct wolf populations. The Eastern Eurasian dog then traveled by migrating to Western Europe between 14,000-6,400 YBP in which they replaced some European dogs. Two domestic events in Western Eurasia and Eastern Eurasia were recently found for domestic pigs.
The proposed hypothesis is that the early wolf population split into Eastern and Western Eurasian wolves. These are then tamed independently before becoming extinct. The Western Eurasian dog population was subsequently partially replaced by Asian dogs carried by humans at least 6400 years ago. A single domestication is considered by chance, but double domestication on various sides of the globe is unlikely to occur randomly and it shows that external factors - environmental drivers - may have forced the wolf to work with humans to survive. It is possible that wolves are taking advantage of human resources, or humans may have been introduced to wolves in areas where they had not previously lived.
This study uses radiocarbon ages Newgrange dog to calibrate the mutation rate for dogs, which is similar to that calculated for the Late Pleistocene wolf Taimyr. Comparing the dog sequence Newgrange using the mutation rate of these two modern wolves from Russia allow time difference between 20000-60000 YBP. However, these two modern wolves may not have a close relationship with the population that gave birth to a dog, which may have diverged from their ancestors at a later date.
Dogs neolithic - single domestication event
In 2017, a study comparing nuclear genome sequences from three Neolithic dog specimens from Germany and Ireland with the order of more than 5,000 dogs and wolves. The study found that modern European dogs originated from their Neolithic ancestors without evidence of a population rotation found by previous studies. The study found that one wolf-dog divergence occurred 36,900-41,500 YBP, followed by the difference between the Southeast Asian dog and Western Eurasian dog 17,500-23,900 YBP and this indicates a single dog domestication event occurring between 20,000-40,000 YBP. This study does not support the dual domestication event found by previous studies.
Dog Altai - 33.000 YBP
- Genus Canis, indeterminate species
In 2011, a study looked at 33,000-year-old skulls that were well preserved and left a canopy-like jaw like a dog dug from the Razboinichya Cave in the Altai Mountains in southern Siberia (Central Asia). This morphology is compared to the large Pleistocene wolf skull and mandible of Predmosti, the Czech Republic, the 31,000 YBP, the modern wolves of Europe and North America, and the prehistoric Greenland dogs of the Thule period (1,000 YBP or later) to represent large size but domestic dogs not entirely good. "Razboinichya Cave Cave is almost identical in size and shape to prehistoric Greenland dogs" and not an ancient or modern wolf. However, lower carnassial teeth are lower in the lower value range for prehistoric wolves and are only slightly smaller than modern European wolves, and upper carnassial teeth fall within the reach of modern wolves. "We conclude, therefore, that these specimens can represent dogs in the early stages of domestication, ie newly-made dogs, rather than the deviant wolves... Razboinichya Cave specimens appear to be new dogs... and possibly represent the domestication of wolves plagued by climate change and culture associated with the Last Glacial Maximum. "
In 2007, mtDNA analyzes of the extinct Beringian wolves indicate that two ancient wolves from Ukraine dated 30,000 YBP and 28,000 YBP and 33,000 YBP Altai dogs had the same sequence as six Beringian wolves, showing the same maternal ancestors. In 2013, a DNA study of the Altai dogs stores the GenBank sequence with the classification Canis lupus familiaris (dog). "The analysis reveals that the unique haplotype of the Altai dog is more closely related to modern dogs and prehistoric New World canids than contemporary wolves... This initial analysis confirms the conclusion that the Altai specimen is likely to be an ancient dog with a shallow, distinction from an ancient wolf. more ancient about dogs outside the Middle East or East Asia. "The haplotype group closest to the Altai dogs includes diverse races such as Tibetan, Newfoundland, crested Chinese, cocker spaniel and Siberian husky mastiffs.
In November 2013, a study looked at 18 canine fossils and compared them with the complete mitochondrial genome sequences of 49 modern wolves and 77 modern dogs. A more comprehensive analysis of complete mDNA finds that the phylogenetic position of the Altai dog as a dog or wolf can not be inferred and categorizes its sequence as Canis species GenBank access number JX173682. Of the four tests, 2 tests show the sequence falls in a wolf clade and 2 tests in a dog clade. The sequence strongly indicates the position at the roots of the clade that unites two ancient wolf genomes, two modern wolves, and two Scandinavian dogs. However, this study does not support its recent ancestors with most modern dogs. This study suggests that it may represent a failed episode of domestication. If so, there may be initially more than one ancient domestication event for dogs because there are domestic pigs.
By 2017, two prominent evolutionary biologists review all available evidence of dog irregularities and support specimens from the Altai mountains as dogs from the now extinct lineage come from the now extinct wolf populations.
Archaeological evidence
Pet dogs are more clearly identified when they are related to human work, and those adjacent to human remains provide the most convincing evidence, (see table below - 14,708 Bonn-Oberkassel YBP dogs).
The table below lists the proposals of the early dog ​​specimens, their location, and the time in the preceding few years (a preliminary estimate of the initial and latest estimates provided) and the color code as purple - Western Eurasia , red - Eastern Eurasia and green - Central Eurasia. Archaeological evidence suggests the first dog remains found early in Western Eurasia and Eastern Eurasia, but not among them in Central Asia until much later.
Dog domestication
Animal apology is a scientific theory of the mutual relationship between animals and humans that have an influence on their care and reproduction. Charles Darwin recognizes a small number of traits that make domestic species different from their wild ancestors. He is also the first to recognize the difference between conscious selective breeding in which humans directly opt for the desired trait, and unconscious selection in which trait evolves as a by-product of natural selection or from selection on other traits.
There is a genetic difference between domestic and wild populations. There is also a difference between the characteristics of domestication that important researchers believe in the early stages of domestication, and the nature of the improvements that have arisen since the separation between wild and domestic populations. The properties of domestication are generally fixed in all households, and were selected during the initial episode of the domestication of the animal or plant, whereas the repair properties exist only in benign proportions, although they can be improved in individual breeds or regional populations. Dogs are the first inhabitants and established in Eurasia before the end of the late Pleistocene era, long before cultivation and before the domestication of other animals.
Domestic time
A 2018 domestication study looks at the reasons why archaeological records based on fossil dating remain often distinct from the genetic record contained in the cells of living species. This study concludes that our inability to domesticate at this time is because domestication is a continuum and there is not a single point where we can say that a species is clearly tamed using both of these techniques. The study proposes that cross-time morphological changes and how humans interact with species in the past need to be considered in addition to these two techniques.
Peak predators are predators at the top of the food chain, while mesopredators are under the food chain and depend on smaller animals. Toward the end of the Pleistocene era, most of today's top predators are mesopredators and these include wolves. During the ecological upheaval associated with the closing of the Pleistocene End, one type of wolf population rose to its peak predator today and the other joined humans to become top consumers.
In August 2015, a study conducted a complete mitogenome sequence analysis of 555 modern and ancient dogs. The sequence shows an increase in population size of about 23,500 YBP, which coincides with the proposed separation of the current dog and wolf ancestors prior to the Last Glacial Maximum (see first divergence). The tenfold increase in population size occurs after 15,000 YBP, which may be caused by a domestication event and is consistent with the dog's demographic dependence on human populations (see archaeological evidence).
Commensal line
Animal domestication is a coevolutionary process in which populations respond to selective pressures while adapting to new niches that belong to other species with evolving behavior.
- See more: Convergent evolution between dogs and humans
Dogs are a classic example of pets that are likely to take the commensal path to domestication. Dogs are the first inhabitants, and are domesticated and established extensively throughout Eurasia before the end of the Pleistocene, long before the cultivation or domestication of other animals. It may be inevitable that the first pets are from a carnivore sequence because they are less afraid when approaching other species. In the carnivore, the first pet must exist without a diet of all flesh, has the ability to run and hunt to provide its own food, and be a controllable measure to coexist with humans, show the Canidae family, and the temperament that right with the wolf being one of the most gregarious and cooperative animals on the planet.
- See more: Commensal path
Ancient DNA supports the hypothesis that dog domestication precedes the rise of agriculture and begins close to the Last Glacial Maximum of 27,000 YBP when hunter-gatherers prey on megafauna, and when proto-dogs may have taken advantage of the carcasses left on site by early hunters, assist in capturing prey, or provide defense from large competing predators in murder locations. Wolves may be attracted to a human campfire with the smell of cooked meat and garbage dumped around it, first attaching themselves and then considering this as part of their home territory where their warning grunts will remind people of an outsider approach. Wolves likely to be attracted to human camps are less aggressive package members, sub-dominated with lower flight response, higher stress thresholds, less vigilance around humans, and hence better candidates for domestication. The earliest marks of domestication in dogs are neotonization of skull morphology and shortness of muzzle lengths resulting in dental teeth, reduced tooth size, and reduction of number of teeth, which has been associated with strong selection to reduce aggression.. This process may have started during the commensal early stages of dog domestication, even before humans began to become active partners in the process.
Y chromosomes of mitochondrial mothers, fathers, and microsatellite assessments of two werewolf populations in North America and combined with satellite telemetry data reveal significant genetic and morphological differences between a population that migrates with and prey on caribou, and other populations of terrestrial ecotypes that remain in the conifer forest boreal. Although these two populations spend a year in the same place, and although there is evidence of gene flow between them, the differences in prey habitat specialties are sufficient to maintain genetic and even color differences. A study has identified remnants of an extinct Berryian wolf populated population with unique mitochondrial signatures. The shape of the skull, worn teeth, and isotopic signs suggests this is a specialist megafauna hunter and scavenger who became extinct while the less specialized wolf ekotype survived. Similar to the modern wolf-like ecotype that has evolved to track and prey on caribou, the Pleistocene wolf population may begin following cell-hunter gatherers, thus gradually gaining genetic and phenotypic differences that will enable them to more successfully adapt to human habitats.
Even today, the wolves on Ellesmere Island are not afraid of humans, who are considered because they see humans so little, and they will approach humans with caution, curiosity and imminence.
- See more: Megafaunal wolf
Post-domestication gene flow
Several studies have found greater diversity in dog genetic markers from East and Central Asia compared with Europe and have concluded that dogs originate from this area, although there is no archaeological evidence to support the conclusion. One of the reasons for this difference is the continued mixing between different dog and wolf populations in the Old World and the New World for at least the last 10,000 years, which have obscured the genetic signatures and attempts of confusing researchers in determining the origin of dogs. Another reason is that no modern wolf population is associated with the first preyed Pleistocene wolf. In other words, the extinction of the wolf who is the direct ancestor of the dog has been muddling efforts to determine the time and place of dog domestication.
- See more: Post-domestication gene flow
Wolf-Dog Hybridization
Phylogenetic analysis showed that mAPNA modern dog haplotypes resolved into four monophyletic clad with strong statistical support, and this has been designated by researchers as A-D clades. Other studies that included a wider sample of specimens have reported two rare East Asian clones of E-F with weaker statistical support. In 2009, a study found that haplogroups A, B, and C accounted for 98% of dogs and were found to be universally dispersed across Eurasia, indicating that they were the result of one occurrence of domestication, and that haplogroups D, E, and F were rare and appears to be the result of regional hybridization with local wolves after domestication. Haplogroups A and B contain subclasses that appear to be the result of hybridization with the post-domestication wolf, because each haplotype in each of these subclasses is the result of the female/male wolf pair.
Haplogroup A: Includes 64-65% of dogs. The a2-a6 subclass haplotype is derived from wolf-dog hybridization post-domestication.
Haplogroup B: Includes 22-23% of dogs. haplotype subclade b2 is derived from wolf-dog hybridization post-domestication.
Haplogroup C: Includes 10-12% of dogs.
Haplogroup D: Derived from post-domestic wolf-dog hybridization in subclade d1 (Scandinavia) and d2 (South-West Asia). Sub-clones sub-hybrid Sk1 d1 north comes from 480-3000 YBP and is found in all related breeds Sami: Lapphund Finland, Lapphund Sweden, Herder Lapponian, Jamthund, Norwegian Elkhound and HÃÆ'¤llefors Elkhound. The series of wolf mothers who contribute to them have not been matched across Eurasia and their branches are phylogenetically rooted in the same sequence as the Altai dog (not the direct ancestor). Subclasses d2 hybrid haplotypes are found in 2.6% of South-West Asian dogs.
Haplogroup E: Derived from post-domestication wolf-dog hybridization in East Asia (rare distribution in Southeast Asia, Korea and Japan).
Haplogroup F: Derived from post-domestication wolf-dog hybridization in Japan. A study of 600 dog specimens found only one dog whose sequence indicates hybridization with an extinct Japanese wolf.
It is not known whether this hybridization is the result of humans choosing the phenotypic nature of the local wolf population or the result of natural introgression as the dog extends across Eurasia.
In 2018, a study found a small number of dog ancestors in 62% of Eurasian wolf specimens observed, that hybridization has occurred at various timescales rather than just recently, but otherwise there is hardly any mixing detected in North America. specimen. There is a male dog introgression to the wolf, but also one detectable hybrid that is the result of a male wolf crossed with a female dog. Wolves have retained their phenotype differences from dogs, which show low frequency hybridization. The conclusion is that the phenotype is not an indication of "purity" and the definition of pure wolf is ambiguous. Dogs that can be free throughout Eurasia show the introgression of the wolf. Another study found that the -defensin gene responsible for the North American wolf's black coat was the result of a single introgression of dogs in the Yukon dates between 1,600-7,200 years ago. The study proposes that early American native dogs are the source.
Taimyr Wolf mix
In May 2015, a study compares the ancestry of Taimyr-1 wolf lineage with dogs and gray wolves.
A comparison with the gray wolf lineage indicates that Taimyr-1 is a basal for gray wolves from the Middle East, China, Europe and North America but shares a large amount of history with the current gray wolfs after their distinction from the coyotes. This implies that the ancestral majority of the gray wolf population today comes from an ancestral population that lived less than 35,000 years ago, but before the inundation of Tanah Bering Bridge with subsequent isolation from the Eurasian and North American wolves.
The ancestral comparison of the Taimyr-1 lineage with dog lineage suggests that some modern dog breeds have a closer relationship with gray wolves or Taimyr-1 due to mixing. The Saarloos wolfdog shows more associations with the gray wolf, which corresponds to a documented history crossbreeding with the gray wolf in this breed. Taimyr-1 shares more alleles (ie gene expression) with offspring associated with high latitudes - Siberian husky and Greenland dogs also associated with polar human populations, and to a lesser extent Shar Pei and Finnish spitz. The Greenland dog mixing chart shows the best match of 3.5% sharing material, although the proportion of ancestors ranged between 1.4% and 27.3% consistent with the data. This shows the mixing between the Taimyr-1 population and the ancestral dog population of these four high-latitude breeds. These results can be explained either by the very early presence of dogs in northern Eurasia or by the genetic heritage of Taimyr-1 preserved in the northern wolf population until the arrival of dogs at high latitudes. This introgression can provide early-age dogs living in high latitudes with phenotypic variations that are useful to adapt to new and challenging environments. It also shows that the ancestors of today's dog breeds descend from more than one region.
Attempts to explore the mixing between the Taimyr-1 wolf and the gray wolf produce unreliable results.
As the Taimyr wolf has contributed to the genetic makeup of the Arctic descendants, a later study showed that the descendants of the Taimyr wolf survived until the dogs were domesticated in Europe and arrived at high latitudes where they mixed with local wolves, and both contributed to modern Arctic descent. Based on the remains of the oldest most accepted zooarchaeological dog, domestic dogs most likely arrive at high latitudes in the last 15,000 years. The rate of calibrated mutations of the Taimyr wolf and the genomes of Newgrange dogs suggests that the populations of wolves and modern dogs deviate from a common ancestor between 20,000 and 60,000 YBP. This shows that the dogs were tamed earlier than their first appearance in archaeological records, or they arrived at the Arctic early, or both.
Positive choice
Charles Darwin recognizes a small number of traits that make domestic species different from their wild ancestors. He is also the first to recognize the difference between conscious selective breeding in which humans directly opt for the desired trait, and unconscious selection in which trait evolves as a by-product of natural selection or from selection on other traits. Domestic animals have variations of fur colors as well as textures, dwarfs and giant varieties, and changes in their reproductive cycles, and many others that have floppy teeth and ears.
While it is easy to assume that each of these traits was uniquely selected by early hunter-gatherers and peasants, beginning in 1959 Dmitry Belyayev tested the reaction of the silver fox with the hand placed in their cage and chose the tamest, the least aggressive individual to breed. The hypothesis is that, by choosing behavioral traits, he can also influence the next generation phenotype, making them more in appearance. Over the next 40 years, he succeeded in producing foxes with features that were never directly chosen, including a dappled floppy ears, an upturned tail, a short snout, and a shift in development time. In the 1980s, a researcher used a series of phenotypic, behavioral, cognitive, and visible markers, such as feather color, to produce fallow deer in several generations. Similar results for tameness and fear have been found for Japanese sterling and quail. In addition to suggesting that domestic phenotypic properties can arise through selection for behavioral traits, and the nature of domestic behavior can arise through selection for phenotypic traits, this experiment provides a mechanism for explaining how the domestication process of animals can begin without intentional human thought. and action.
The genetic differences between the domestic and wild populations can be framed in two considerations. The first distinguishes between the domestication attributes considered important at the early stages of domestication, and the nature of the improvements that have arisen since the separation between wild and domestic populations. The dominant traits are generally fixed in all households and are selected during the initial episode of domestication, whereas the repair properties are only in the proportion of domestication, although these traits can be corrected in individual breeds or regional populations. A second problem is whether the characteristics associated with domestic syndrome result from selection relaxation when the animal comes out of the wild or from a positive selection resulting from intentional and unintentional human preferences. Several recent genome studies on the genetic basis of traits associated with domestication syndrome have explained these two problems. A study published in 2016 shows that there is a negative genetic consequence of the domestication process as well, that enrichment of gene variants associated with the disease with positive properties are selected.
In 2010, a study identified 51 areas of the dog's genome associated with phenotypic variation among breeds in 57 features studied, which included the shape and size of bones, teeth, teeth, and long bones. There are 3 loci quantitative properties that explain most of the phenotypic variations. The recent selection indicator is indicated by many of the 51 genomic regions associated with the defining properties of the breed, which includes body size, coat characteristics, and ear floppiness. Genetics has identified more than 300 genetic loci and 150 genes associated with the color variability of the mantle. Knowing mutations associated with different colors has allowed a correlation between the time of color of the variable feathers on horses with their domestication time. Other studies have shown how human-induced selection is responsible for allele variation in pigs. Together, these insights show that, although natural selection has made variations to a minimum before domestication, humans have been actively selected for new mantle colors as soon as they appear in managed populations.
In 2015, a study looked at more than 100 pig genomes sequences to confirm their domestication process. A model corresponding to the data includes mixing with wild pig ghost populations that are already extinct during the Pleistocene. The study also found that although re-crossing with wild pigs, the domestic pig's genome has a strong selection mark in the genetic locus that affects behavior and morphology. This study concludes that human selection for domestic characteristics may neutralize the effect of homogenizing gene flow from wild boar and creating the domestication islands in the genome. The same process may also apply to other pets.
In 2014, a whole genome study of DNA differences between wolves and dogs found that dogs did not show a diminished fear response but showed greater synapses of plasticity. Synaptic plasticity is widely believed to be a correlation of cellular learning and memory, and this change may have altered the learning and memory capabilities of dogs compared to wolves.
Behavior
Unlike other domestic species that are primarily selected for properties associated with production, dogs were initially selected for their behavior. By 2016, a study found that there are only 11 fixed genes that show variations between wolves and dogs. This gene variation is unlikely to be the result of natural evolution, and shows selection in both morphology and behavior during dog domestication. There is evidence of selection during the domestication of dog genes that influence the pathways of adrenaline and noradrenaline biosynthesis. These genes are involved in the synthesis, transport and degradation of various neurotransmitters, particularly catecholamines, which include dopamine and noradrenaline. Repeated selection on this pathway and its role in emotional processing and fight-or-flight responses suggests that the behavioral changes we see in dogs compared to wolves may be due to changes in these pathways, leading to slippage and emotional processing abilities. Dogs generally show less fear and aggression than wolves. Some of these genes have been linked to aggression in some dog breeds, indicating their importance in early domestication and later in breed formation.
Adaptation diet
AMY2B (Alpha-Amylase 2B) is a gene that encodes proteins that help with the first step in the digestion of food starch and glycogen. The expansion of this gene in dogs will allow early dogs to exploit a starch-rich diet as they are fed from agriculture. In a study in 2014, the data show that wolves and dingo have only two copies of genes and the Siberian Husky associated with hunter-gatherers has only three or four copies, while Saluki is associated with the Fertile Crescent where the farm comes from 29 copies. The results show that on average, modern dogs have a high number of gene copies, whereas wolves and dingo do not. The high number of copies of the AMY2B variant may have existed as a real variation in early domestic dogs, but has been expanded recently with the development of a large agriculture-based civilization. This suggests that at the beginning of the domestication process, dogs may have been characterized by a carnivorous diet more than their modern counterparts, a diet shared with early hunter-gatherers. A later study showed that because most dogs have a high number of copies of the AMY2B gene but the Arctic and dingo races do not, that dietary changes in dogs may not be caused by early domestication but by subsequent agricultural deployment to a large extent - but not all - regions of the planet this.
In 2016, the study of dog genomes compared to the wolf genome looked for genes that showed signs of having had a positive selection. The study identified genes related to brain function and behavior, and lipid metabolism. The ability to process these lipids shows important food selection targets when proto-dogs are hunted and fed with hunter-gatherers. The evolution of dietary metabolic genes may have helped to process the increase in lipid content of the early dog ​​diet when they scavenged the remains of carcasses left behind by hunter-gatherers. The rate of catching prey may have increased compared to the wolves and hence the amount of lipids consumed by the proto-dogs are helpful. The unique food selection pressure may have evolved both from the amount consumed, and the shifting composition of, the tissues available to proto-dogs after humans have removed the most desirable part of the carcass for themselves. A study of mammalian biomass during modern human expansion into northern Mammoth grassland found that it occurred under unlimited resource conditions, and that many animals were killed with only a small portion consumed or not used.
- See more: Phenotypic plasticity
Natural selection
The dog can infer the name of an object and has been shown to study n
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