+ New Study: Dogs Originated in Middle East

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Using  methods for studying the genetics of humans, researchers have concluded that dogs were probably first domesticated from wolves somewhere in the Middle East. 

An earlier survey suggested that dogs originated in East Asia.

According to Nicholas Wade’s article in the NY Times,  the new research places dog domestication in the same place as the domestication of plants and other animals — which was also the place where agriculture was invented about 10,000 years ago.

The research team was led by Bridgett M. vonHoldt and Robert K. Wayne of UCLA.  According to Wayne, professor of  ecology and evolutionary biology, 

Dogs seem to share more genetic similarity with Middle Eastern gray wolves than with any other wolf population worldwide.  Genome-wide analysis now directly suggests a Middle East origin for modern dogs.  We have found that a dominant proportion of modern dogs’ ancestry derives from Middle Eastern wolves, and this finding is consistent with the hypothesis that dogs originated in the Middle East.

VonHoldt, a graduate student and the lead author, says that in this study they used a broader sampling of wolves globally than has ever been done before.  She says

In our analysis of the entire genome, we found that dogs share more unique markers with Middle Easter wolves than with East Asian wolves.  We used a genome-wide approach, which avoids the bias of single genome region. 

Archaeological evidence also supports the researchers’ conclusions, since some of the earliest dog remains have been found in the Middle East, dating from12,000 years ago.

The only earlier doglike remains occur in Belgium at a site 31,000 years old, and in western Russia from 15,000 years ago.

What were humans doing at the time?  We were hunters and gatherers (as we have been for most of our existence).   Wolves began following hunter-gatherer bands to feed on their wounded prey, leftover carcasses or refuse, thinks Wayne.

Then at some point a group of wolves, who happened to be smaller and less threatening than most, developed a dependency on human groups. 

They may, in return, have provided a warning system. 

Several thousand years later, around 15,000 years ago, the first settled communities began to appear in the Middle East.  People began intervening in the breeding patterns of their animals, turning them into the first “proto” dogs.

One of the features they selected was small size.  According to Wayne, “I think a long history such as that would explain how a large carnivore, which can eat you, eventually became stably incorporated in human society.”

When the team used the dog SNP chip to scan for genes that show signatures of selection, Wayne was surprised to learn that all the herding dogs grouped together.  All the sight hounds and the scent hounds grouped as well.  So perfect matches were made between dogs’ various functions and the branches on the genetic tree.

I thought there would be many ways to build a herding dog and that they’d come from all over the tree, but there are not.

One favored dog gene has a human counterpart that has been implicated in Williams syndrome, where it causes exceptional gregariousness.

Two others are involved in memory.  Dogs, but not wolves, are good at taking cues from human body language.  The two genes might have something to do with this

Other experts on dog genetics, Carlos Driscoll and Stephen O’Brien of the National Cancer Institute, believe vonHoldt and Wayne have made a convincing case.

Some conjectures:

Since dog domestication and human settlement occurred at the same time, some have raised the possibility that dogs may have had a complex impact on the structure of human society.   They might have been sentries — they would make it possible for hunter gatherers settle in place without fear of suprise attacks.

They also might have been the first items of inherited wealth — preceding cattle. 

In this way they could have laid the foundations for the gradations of wealth and social hierarchy that differentiated settled groups from the previous egalitarianism of the hunter gatherers.  Dr. Driscoll suggests that notions of inheritance and ownership may have been prompted by the first dogs to permeate human society, laying an unexpected track from wolf to wealth.

sources: Nicholas Wade’s NY Times article on 3/18/10 (www.nytimes.com) and UCLA newsrelease article by Stuart Wolpert (www.newsroom.ucla.edu)

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