We've all heard the phrase “dog is man's best friend.”
我们都听过这句话“狗是人类最好的朋友”。
But how did dogs get to be so friendly with humans?
但是为什么狗对人类那么友好呢？
It turns out that dog domestication wasn't simply a matter of teaching Fido to play “fetch.”
事实证明狗的驯化并不是简单教会狗接住东西。
Scientific research indicates that genetic selection played a key role as well.
科学家的研究表明，遗传选择也起到了一个重要的作用。
We know that dog domestication began over ten thousand years ago.
我们知道狗的驯化开始于一万多年前。

However, scientists have yet to reach a consensus on the details of how and why certain ancient wolves evolved into our furry canine friends.
但是，科学家并未就远古狼如何以及为何演变成我们毛茸茸的犬类朋友而达成共识，并得到相关细节。
Those details are getting clearer, though, thanks to a group of scientists working in Sweden and the United States.
但是得感谢瑞典和美国的一组科学家，他们让这些细节变得明朗。
They analyzed the DNA from a dozen wolves and sixty dogs to determine which genetic markers distinguish domestic canines.
他们分析了12只狼和60只狗的DNA，确定哪种遗传标记区别于被驯化的狗。
In total, 122 specific genes that could be linked to domestication turned up.
总共有122个特定基因被证实与已经驯化的狗有联系。
Probably the most illuminating discovery was the importance of three of those genes to doggie diet: they help with starch digestion.
可能最具启蒙性的发现是，三个关于狗饮食的基因的重要性:他们帮助淀粉消化。
It turns out that dogs possess significantly more copies of these genes than wolves do.
这被证实,狗比狼更多的复制了这些基因。
As a result, your family pet is about five times better than its carnivorous relatives at digesting starchy foods like potatoes and rice.
结果就是你的狗比它的食肉亲戚在消化淀粉类食物,如土豆和大米方面大约强五倍。
This genetic evidence links the most recent phase of canine evolution to human history: during the shift from a hunter gatherer to an agricultural society, we started eating more starch, too.
基因证据表明，狗的进化与人类社会的历史发展有关联:从狩猎社会到农业社会,人类开始食用更多的淀粉食物。
Waste dumps near new human settlements would have provided an ideal place for canines to scavenge food–but only if they were willing to trade in carnivorous cravings for a more starchy supper.
废弃垃圾场就在人类的住所附近，这也为犬类提供了理想的觅食场所，但前提是它们愿意放弃肉食而选择淀粉类食物。
So, there you have it: your pooch isn't merely your best friend–it's also your evolutionary partner!
所以，要知道，你的狗不仅仅是你最好的朋友，它也是你一同进化的小伙伴。