英语听力文摘 English Digest 705 狗是如何成为人类朋友的？（在线收听）

How Did Dogs Become “Man’s Best Friend?”

We’ve all heard the phrase “dog is man’s best friend.” But how did dogs get to be so friendly with humans? It turns out that dog domestication wasn’t simply a matter of teaching Fido to play “fetch.” Scientific research indicates that genetic selection played a key role as well.

Dog Domestication

We know that dog domestication began over ten thousand years ago. However, scientists have yet to reach a consensus on the details of how and why certain ancient wolves evolved into our furry canine friends.

Those details are getting clearer, though, thanks to a group of scientists working in Sweden and the United States. They analyzed the DNA from a dozen wolves and sixty dogs to determine which genetic markers distinguish domestic canines. In total, 122 specific genes that could be linked to domestication turned up.

Doggie Diet

Probably the most illuminating discovery was the importance of three of those genes to doggie diet: they help with starch digestion. It turns out that dogs possess significantly more copies of these genes than wolves do. As a result, your family pet is about five times better than its carnivorous relatives at digesting starchy foods like potatoes and rice.

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. 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.

So, there you have it: your pooch isn’t merely your best friend–it’s also your evolutionary partner!

狗是如何成为人类朋友的？

我们都听过“狗是人类最好的朋友”这句话。但是，狗是如何与人类如此友好的呢？事实证明，驯化狗不仅仅是教菲多玩“fetch”游戏。科学研究表明，基因选择也发挥了关键作用。

狗的驯化

我们知道狗的驯化始于一万多年前。然而，科学家们尚未就某些古代狼如何以及为什么进化成我们毛茸茸的狗朋友的细节达成共识。

然而，由于一群在瑞典和美国工作的科学家，这些细节越来越清晰。他们分析了12只狼和60只狗的DNA，以确定哪些遗传标记可以区分家养犬科动物。总共发现了122个与驯化有关的特定基因。

狗狗饮食

最具启发性的发现可能是其中三种基因对狗狗饮食的重要性：它们有助于淀粉消化。事实证明，狗比狼拥有更多的这些基因拷贝。因此，你的家庭宠物在消化土豆和大米等淀粉类食物方面比它的食肉亲戚好五倍。

这一基因证据将犬类进化的最新阶段与人类历史联系起来：在从狩猎采集者向农业社会转变的过程中，我们也开始吃更多的淀粉。新人类住区附近的垃圾场将为犬科动物提供一个理想的觅食场所——但前提是它们愿意以肉食性的渴望换取更淀粉的晚餐。

所以，你就明白了：你的狗不仅是你最好的朋友，它还是你的进化伙伴！