A religiously inspired change in the European diet about a thousand years ago led to the development of the modern domesticated chicken. 

大约一千年前，一场由宗教引发的欧洲饮食改变导致了现代家养鸡的发展。 

撰文/播音：卡伦·霍普金（Karen Hopkin） 

翻译：郭鑫鹏 

审校：郭晓 

Why did the chicken cross the road? Well, that’s a philosophical pickle. But if you want to know why chickens don’t get cross at people-why they’re content being kept in their coops-science can help. 

鸡为什么过马路？那是一个哲学难题。但是如果你想知道鸡为什么顺从于人类，也就是说为什么它们甘于被关在笼子里，那么科学可以提供答案。 

“Domestic species are interesting because their genetic makeup has changed dramatically as part of the process of going from wild to domestic.” 

“家养动物非常有趣，因为在从野生到家养的过程中，它们的基因组成发生了显著的变化。” 

Liisa Loog, an evolutionary geneticist and anthropologist at the Universities of Oxford and Cambridge. 

牛津和剑桥大学进化遗传学家和人类学家莉萨·莱格说。 

“And indeed when people have compared modern domestic animals with their wild relatives they’ve identified genes that do show signs of strong recent selection. One such gene is thyroid stimulating hormone receptor, otherwise known as TSHR…in chickens, a variant of this gene that is widespread in modern populations has been shown to directly cause chickens to be less fearful of humans and also result in reduced aggression towards conspecifics.” 

“的确，当人们比较现代家养动物和它们的野生同类时，他们发现了有着极强近期选择性迹象的基因。其中一个基因是促甲状腺激素受体，也被称作TSHR。这个基因的一个变种在现代鸡种群中传播很广，它直接导致鸡不那么怕人类，也降低了鸡对同类的攻击性。 

But when exactly did the selection for these traits-and therefore this variant-take place? 

但是这些特征的选择以及由此产生的变种到底是什么时候发生的？ 

“It’s been suggested because of the potential usefulness of these traits in domestic setting that selection on this gene must have happened when chickens were first domesticated around 6,000 years ago in East Asia. But in an evolutionary timescale this is just a blink of an eye and we just don’t know and don’t have the resolution to tell when exactly between 6,000 years ago and now this selection happened, using data from only modern chicken populations…but with DNA from archaeological material we can follow what happened with a gene through time and in theory spot when changes in a population occur.” 

因为这些特征在驯养环境中发挥着潜在的作用，因此有人认为这个基因的选择一定是发生在6000年前东亚地区的人们第一次驯养鸡的时候。但是在一个进化的时间尺度上，这只是一眨眼的事情，单凭现代鸡种群的数据，我们并不知道也无法确定这个选择到底发生在6000年前至今的哪个时间点。但是有了考古材料中的DNA，我们就可以追踪一个基因随着时间的变化，并在理论上确定一个种群何时发生了变化。” 

Loog and her colleagues examined TSHR gene sequences in the ancient remains of about 60 chickens found in Europe “and estimated that selection at this TSHR locus happened only around 1,000 years ago, at medieval times. That is, 5,000 years after the initial domestication of chicken. 

莱格和她的同事们检测了TSHR基因序列，这些基因序列来自于在欧洲发现的约60只鸡的遗骸，他们估计TSHR的基因选择仅仅发生在大约1000年前，也就是中世纪时期。那时距离最初的鸡驯养已经过了5000年。 

“Interestingly this time period coincides with a…substantial increase in chicken consumption known from the archaeological record. Historians suggest that a key driver behind these changes was the rising popularity and spread of Christian traditions, which discouraged and also on occasions even banned eating meat from four-legged animals.” 

“有趣的是，我们从考古学记录中知道，在那个时期，鸡肉消费也出现了巨大的增长。历史学家认为这些变化背后的一个关键要素是基督教受欢迎度的增加及其传播范围的扩大，因为基督教不提倡，有时甚至禁止人们食用4只腿的动物。“ 

But fowl were fair game. 

但是家禽是准许食用的。 

“What is really exciting about this new study is that for the first time we can directly link genetic changes in domestic animal with cultural shifts in human food preference. The findings appear in the journal Molecular Biology and Evolution. [Liisa Loog et al., Inferring allele frequency trajectories from ancient DNA indicates that selection on a chicken gene coincided with changes in medieval husbandry practices] 

“而这项新研究真正让人激动的是，我们第一次把家养动物基因上的变化与人类食物偏好的文化转变直接联系在了一起。”这项发现发表在期刊《分子生物学和进化》上。 

This kind of plucky study is not just for the birds. Loog says the team is collecting canine archaeological samples, so they can look at how man’s best friend got divvied up into so many different breeds. Their research will no doubt be dogged. 

这类大胆的研究并不只是针对鸟禽们。莱格说她的团队正在收集犬类考古学样本，他们准备研究人类最好的朋友是如何被分为了如此多不同的品种。毫无疑问我们会继续追踪他们的研究。 

-Karen Hopkin