A 33,000-year-old dog skull unearthed in a Siberian mountain cave presents some of the oldest known evidence of dog domestication and, together with an equally ancient find in a cave in Belgium, indicates that modern dogs may be descended from multiple ancestors.I've been following the dog domestication saga for a few years now; it seems that geneticists are in general agreement that domestic dogs share a fairly recent ancestry from East Asia, although there are some lingering controversies about the role of other dogs in the formation of modern breeds. On the contrary, there are now two cases of Upper Paleolithic domesticated dogs, from both Belgium and Siberia. I can't wrap my head around the idea that dogs that were domesticated more than 30 thousand years ago, and would -presumably- have plenty of time to adapt would be totally replaced.
It would be great if we could get some Paleolithic dog DNA for comparison, as this would show whether some modern dog breeds are differentially affiliated to Paleolithic dogs, which would support a "multiregional evolution of domestic dogs".
PLoS ONE 6(7): e22821. doi:10.1371/journal.pone.0022821
A 33,000-Year-Old Incipient Dog from the Altai Mountains of Siberia: Evidence of the Earliest Domestication Disrupted by the Last Glacial Maximum
Nikolai D. Ovodov et al.
Abstract
Background
Virtually all well-documented remains of early domestic dog (Canis familiaris) come from the late Glacial and early Holocene periods (ca. 14,000–9000 calendar years ago, cal BP), with few putative dogs found prior to the Last Glacial Maximum (LGM, ca. 26,500–19,000 cal BP). The dearth of pre-LGM dog-like canids and incomplete state of their preservation has until now prevented an understanding of the morphological features of transitional forms between wild wolves and domesticated dogs in temporal perspective.
Methodology/Principal Finding
We describe the well-preserved remains of a dog-like canid from the Razboinichya Cave (Altai Mountains of southern Siberia). Because of the extraordinary preservation of the material, including skull, mandibles (both sides) and teeth, it was possible to conduct a complete morphological description and comparison with representative examples of pre-LGM wild wolves, modern wolves, prehistoric domesticated dogs, and early dog-like canids, using morphological criteria to distinguish between wolves and dogs. It was found that the Razboinichya Cave individual is most similar to fully domesticated dogs from Greenland (about 1000 years old), and unlike ancient and modern wolves, and putative dogs from Eliseevichi I site in central Russia. Direct AMS radiocarbon dating of the skull and mandible of the Razboinichya canid conducted in three independent laboratories resulted in highly compatible ages, with average value of ca. 33,000 cal BP.
Conclusions/Significance
The Razboinichya Cave specimen appears to be an incipient dog that did not give rise to late Glacial – early Holocene lineages and probably represents wolf domestication disrupted by the climatic and cultural changes associated with the LGM. The two earliest incipient dogs from Western Europe (Goyet, Belguim) and Siberia (Razboinichya), separated by thousands of kilometers, show that dog domestication was multiregional, and thus had no single place of origin (as some DNA data have suggested) and subsequent spread.
Link
I think the problems with past studies is that they compare Europe where dogs have been intensively selectively bred for the last few hundred years with areas where there is more natural diversity. There are no true village dogs in Europe, just a few revertants. The intensively bred group can be expected to be a small sub population of the original group of domestic dogs, and that is what we see. Just because the diversity still exists in East Asia does not mean that it originated there. Just that there has been less selective breeding there. Incidentally this 33k Siberian dog was found in the Altai mountains which I regard as central asia. The Belgian dog was embedded in the Aurignacian culture.
ReplyDeleteIMO dog were domesticated by the time of the Gravettian culture (32-22k ya). And this culture stretched along the snowline from at least Berengia/Siberia to Belgium-ish. Ancient dogs can be expected to have been mixing across the breadth of northern Eurasia at that time. It is logical that more of the original population can be found in East Asia today as compared to Western Europe where dogs reach a kind of extreme fetish status, and haven't really free-bred for as far back as we can remember.
All dogs originated with the grey wolf which was the worlds most widespread mammal. Everywhere but Africa, Australia and South America. Grey wolves can be domesticated today. Some studies (molecular clock) put the separation of dogs and wolves at 100k ya which is not inconceivable.
Dogs had to have been first domesticated in the territory of the grey wolf. The two oldest dogs are in Aurignacian Belgium and in the Altai mountains. These two areas have to be our best candidates at the moment until the archaelogy develops. There is no true evidence of an East asian origin as the genetics is entirely consistent ancient spread along the snow line followed by intensive selection in Europe reducing diversity.
There a lot of things that a human will do but a dog won't.
ReplyDeleteI think dogs are way too valuable to be multiple-location, several millennia apart, random occurrences.
ReplyDeleteAMHs definitely benefited from dogs at some time when hunting and tracing injured game, and likely also to protect pregnant women/children/elderly home groups while the strongest males and females were out hunting. A definite advantage when compared to Neanderthal or what-not natives - and of course also warning against their approach.
I can't wrap my head around the idea that dogs that were domesticated more than 30 thousand years ago, and would -presumably- have plenty of time to adapt would be totally replaced.
ReplyDeleteI would question whether the signals of domestication would necessarily correlate with the existence of an enormously important feature found in modern dogs: the ability to "read human communicative signals indicating the location of hidden food," [Hare et al. (2002)] as well as other social signals. Although this feature appears similar to that of human infants, there also appear to be differences, suggesting "that shared sensitivity to human communicative signals stems from convergent social evolution of the Homo and the Canis genera." [Topál et al. (2009)]
If this feature is based on a very-low-probability homeotic mutation (IMO very likely) There might have been many abortive events of wolf domestication where the line died out because the domesticated wolves simply weren't valuable enough without the feature mentioned above.
Ref's:
B. Hare, M. Brown, C. Williamson, M. Tomasello (2002) The Domestication of Social Cognition in Dogs Science 298, 1634 (2002)DOI: 10.1126/science.1072702
J. Topál, G. Gergely, A. Erdohegyi, G. Csibra, A. Miklósi (2009) Differential sensitivity to human communication in dogs, wolves, and human infants Science 325, 1269 (2009) DOI: 10.1126/science.1176960
I don't think the paper's definition of domestication is necessarily all that obvious:
ReplyDelete"We conclude that the lineage represented by the incipient dog from Razboinichya Cave did not survive the LGM."
"Traditional anthropological definitions of domestication consider the process to be a deliberate act of selection by humans [1]. However, this view has been challenged in recent years by the hypothesis that animals colonized anthropogenic environments of their own volition and evolved into new (“domestic”) species via natural evolutionary processes because it better fits a number of associated observations, including the evidence from genetics that domestication took place multiple times over geographic space and chronological time in virtually all mammalian taxa [2], [43]. After initial changes occurred, the resulting new species were modified during their association with people via natural adaptation, human selection, and genetic drift."
"Since dog domestication almost certainly occurred multiple times without direct human selection, we suggest that it must have occasionally failed. That is, the particular set of ecological conditions associated with human settlement and hunting practices that were necessary to initiate the domestication process must have, on some occasions, existed only long enough to produce a few modified wolves (i.e. incipient dogs) with short-lived lineages."
"We suggest that the pre-LGM Goyet and Razboinichya canids are unlikely to be the ancestors of post-LGM dogs. These canids most probably are both “proto” or incipient dogs that did not persist long enough to found enduring lineages, since no putative dog remains have been found at adjacent sites in western and central Europe and in Siberia occupied during the LGM."
"Remains of both incipient dogs and early true dogs are critical indicators that a particular set of natural ecological conditions and human-mediated social factors existed at certain times in the past. Mapping the geographic extent and chronological order of these events enriches our understanding of human history and evolutionary processes. The fact that the Razboinichya canid is likely an early incipient dog rather than the oldest ancestor of modern dogs in no way detracts from its historical or biological importance."
That being the case, it seems the paper is only arguing that canids that are physiologically incipient dogs have arisen before the LGM. I reckon DNA studies would be necessary for anything further - the archaeological data is too scarce and, as per the authors, the physical features may or may not have been the result of active human domestication.
The National Geographic article states that they have only found European dog DNA in the Americas so far and that they are looking for pre-European dogs in obscure places.
ReplyDeleteI'm not surprised. I think domestication of the dog has a lot to do with domestication of humans, and around thirty thousand years ago the environment was starting to shift, so to where humans and our long time (we're been hanging around each other for millions of years) companions wolves.
ReplyDelete"It would be great if we could get some Paleolithic dog DNA for comparison, as this would show whether some modern dog breeds are differentially affiliated to Paleolithic dogs, which would support a "multiregional evolution of domestic dogs"."
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So true! AND.. might not humans be giving themselves more credit for the "dog" than they deserve? Has the possibility that the dog was, and is to this day, a seperate breed of wolf been totally ruled out? I don't mean to detract from human intelligence and skill ~30Kyr ago, or even ~10Kyr ago, but why should a breed of wolf, which was "slightly different" in build and temperment, have not roamed the area with man and wolf and fox, etc.? Sometimes we are responsible for "great" changes, usually we aren't, however, we tend often assume we are. Just wondering. I think we may need more data on the dog.
The paper's case that the dogs whose bones they saw were indeed domesticated isn't helped by the lack of association with hominin bones. These dog bones were found in a hyena cave as a component of hyena dinner.
ReplyDeleteThe argument for domestication is morphological - the dog bones look more like domesticated dogs than wolves. But, maybe it just so happens that they are wild dogs morphologically similar to the dogs that ended up being domesticated, possibly much later.
I think that most researchers underestimate the brutality of paleolithic man. When a people get routed, the men are killed and the dogs eaten or run off. The bottleneck in humans might even be from this; animals don't generally commit genocide, but people do and probably have been since way before the Upper Paleolithic. Y traces back to 40k less than mtdna Eve for this very reason. And how are you gonna keep breeding dogs when you're a nomad constantly fighting other races for survival? Easier to just get a new wolf pup when yours dies.
ReplyDeleteC'mon Andrew. They happen to be morphologically similar to dogs that were domesticated in China 20 thousand years later? Yall do remember that there was the LGM around 19k ago wherein people ate each other in a lot of places to survive? You can always eat your dog and breed some new wolf pups once the world is nice and warm again. Look, people were "domesticating" animals 30k ago in Indonesia by simply bringing them over to islands so that they could hunt them at convenience, and not just chickens. They were also domesticating certain plants then. Any 4 year old kid who finds a nest or wolf pup can domesticate an animal. They just didn't have any reason to SUSTAIN agriculture and domestication, it isn't that they didn't do it.
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