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Thursday, June 2, 2016

Late (Bronze Age?) entry of East Asian dogs into Europe


Open access at Science:

Abstract: The geographic and temporal origins of dogs remain controversial. We generated genetic sequences from 59 ancient dogs and a complete (28x) genome of a late Neolithic dog (dated to ~4800 calendar years before the present) from Ireland. Our analyses revealed a deep split separating modern East Asian and Western Eurasian dogs. Surprisingly, the date of this divergence (~14,000 to 6400 years ago) occurs commensurate with, or several millennia after, the first appearance of dogs in Europe and East Asia. Additional analyses of ancient and modern mitochondrial DNA revealed a sharp discontinuity in haplotype frequencies in Europe. Combined, these results suggest that dogs may have been domesticated independently in Eastern and Western Eurasia from distinct wolf populations. East Eurasian dogs were then possibly transported to Europe with people, where they partially replaced European Paleolithic dogs.

Frantz et al., Genomic and archaeological evidence suggests a dual origin of domestic dogs (June 2, 2016) Science 352 (6290), 1228-1231. [doi:10.1126/science.aaf3161]

See also...

Yamnaya dogs (?)

5 comments:

Karl_K said...

The paper is interesting, but the conclusions are terribly overreaching. They will need much more data to make a valid conclusion on whether there were independent domestication events. To sort out the admixture with local wolves will require lots of very high coverage ancient genomes to look for selected regions.

Shaikorth said...

This is a pretty good article about the dog issue.

http://www.theatlantic.com/science/archive/2016/06/the-origin-of-dogs/484976/


"Here’s the full story, as he [Larson] sees it. Many thousands of years ago, somewhere in western Eurasia, humans domesticated grey wolves. The same thing happened independently, far away in the east. So, at this time, there were two distinct and geographically separated groups of dogs. Let’s call them Ancient Western and Ancient Eastern. Around the Bronze Age, some of the Ancient Eastern dogs migrated westward alongside their human partners, separating from their homebound peers and creating the deep split in Larson’s tree. Along their travels, these migrants encountered the indigenous Ancient Western dogs, mated with them (doggy style, presumably), and effectively replaced them.

Today’s eastern dogs are the descendants of the Ancient Eastern ones. But today’s western dogs (and the Newgrange one) trace most of their ancestry to the Ancient Eastern migrants. Less than 10 percent comes from the Ancient Western dogs, which have since gone extinct."

This is quite similar to an earlier study suggesting dog origins in southern East Asia based on modern sequencing, except western dogs in this model have a small amount of admixture from paleolithic European domestic lineages. Or wolves, in fact this new study has ADMIXTUREGRAPH explaining western dogs as about 7% wolf with the rest coming from similar ancestry to East Asian dogs.

Nirjhar007 said...

Indo-Europeans? .

Alberto said...

@Nirjhar

"Indo-Europeans?"

Pastoralists would probably need dogs and travel with them, so that's a possibility. I miss more samples from the critical time of the possible transition, though. It's only mtDNA, but anyway since they detected this change, it would have been nice to try to get the samples that show the transition.

From Table S5 in the supp. data, what I see is that the last 4 ancient European samples still show the "West Eurasian" mtDNA C and D: 2 from Bury, France (4350 YBP), 1 from Ireland (4200 YBP) and 1 from Italy (4100 YBP).

The ones that carry the "East Asian" mtDNA A are from Siberia (5 out of 5, 6000 YBP) and from Turkmenistan (3 out of 3, 5350-4700 YBP). And Vietnam (2/2, 3700-3200 YBP).

Regarding Turkmenistan, it's interesting that the previous samples from nearby (Tappeh Sang-e Chakhmaq, NE Iran, related to Jeitun culture), still show the "West Eurasian" mtDNA D (7 out of 7, 7900 YBP), so between Jeitun and Margiana there might have been a population change (if the change in the mtDNA of these dog samples is any indication of it).

Interesting, but a follow up with more ancient West Eurasian samples from 5000-3000 YBP would be even more interesting.

Matt said...

Yeah, not totally sure what the evidence is to connect the introduction of East Asian related dogs to the Bronze Age, exactly, at the moment.

The mtdna analysis seems to show its strongest boundary between the 3,040-5,999 vs modern groupings. But I don't know if I have so much confidence that the haplogroup structure of modern dogs in Europe couldn't be transformed by a powerful founder effect? Rather than migration. Anything in the paper anyone else noticed? They have a full sample

Dogs have gone through an extremely high number of generations, compared to people. They're also essentially a product, and you can get a lot of turnover in products.

Also - http://smbe-2016.p.asnevents.com.au/days/2016-07-05/abstract/35626 - "The genomic signature of a 4,600 year old Scandinavian dog adds a time-depth to modern basal dog breeds"