Yardener
Orange Belt
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It's unclear how/when exactly dogs evolved from wolves. One theory is that wolves became domesticated as our hunting companions around 40,000 years ago. Another theory, one bolstered by this recent genetics study, is that wolves became domesticated as a result of feeding on our garbage. This occured once we moved from a hunter/gatherer lifestyle to a more agricultural one around 11,000 years ago.
This study basically compared the wolf genome w/ the domesticated dog and found areas of difference. Then they looked at the genes in those areas and what their funcitons are. Two things: brain and digestion.
The digestion piece is the key evidence here. Dogs have on average 7x the enzyme capacity to digest starches compared to wolves. So, by natural selection, those wolves that could more readily digest our agricultural waste grains had an advantage and passed that trait on.
The brain difference is not as well understood, but probably has to do with the more passive, puppy-like traits that dogs exhibit, which early humans then selected for. (An interesting correlary is a Russian study showing domestication of foxes w/in a few generations by selecting for passivity traits - in the process they develop droopy ears.)
In all likelihood, the domestication of dogs from wolves happened many times w/ many different populations over many thousands of years for different reasons. And those semi-wolf populations then interbred back and forth.
good study summary:
http://www.bbc.co.uk/news/science-environment-21142870
original article:
http://www.nature.com/nature/journal/vaop/ncurrent/full/nature11837.html
This study basically compared the wolf genome w/ the domesticated dog and found areas of difference. Then they looked at the genes in those areas and what their funcitons are. Two things: brain and digestion.
The digestion piece is the key evidence here. Dogs have on average 7x the enzyme capacity to digest starches compared to wolves. So, by natural selection, those wolves that could more readily digest our agricultural waste grains had an advantage and passed that trait on.
The brain difference is not as well understood, but probably has to do with the more passive, puppy-like traits that dogs exhibit, which early humans then selected for. (An interesting correlary is a Russian study showing domestication of foxes w/in a few generations by selecting for passivity traits - in the process they develop droopy ears.)
In all likelihood, the domestication of dogs from wolves happened many times w/ many different populations over many thousands of years for different reasons. And those semi-wolf populations then interbred back and forth.
good study summary:
http://www.bbc.co.uk/news/science-environment-21142870
original article:
http://www.nature.com/nature/journal/vaop/ncurrent/full/nature11837.html