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0Neanderthal DNA may explain why some of us are morning people
尼安德特人DNA里可能有早起的秘密
Scientists find genes inherited from our prehistoric cousins increase tendency to rise early – useful in regions with short winter days
科学家发现，我们从史前表亲那里遗传来的基因增加了早起的倾向——这在冬日白天短的地区很有用
People who are early to bed and early to rise may have their ancient ancestors to thank for the habit – or at least the Neanderthals with whom their forebears procreated, scientists say.
科学家表示，早睡早起的人可能要感谢他们的远古祖先，或者至少要感谢与他们的祖先繁衍后代的尼安德特人。
DNA inherited from our thick-browed cousins may contribute to the tendency of some people to be larks, researchers found, making them more comfortable at getting up and going to bed earlier than others.
研究人员发现，遗传自尼安德特人的DNA可能会导致一些人成为“早鸟”，更喜欢早睡早起。
While most genes that modern humans gained through ancient interbreeding have been weeded out by evolution, a small fraction remain, most probably because they helped early modern humans adapt to the new environment when they left Africa for Eurasia.
虽然现代人类通过古代杂交获得的大多数基因已经被进化淘汰，但仍有一小部分保留下来，很可能是因为它们帮助早期现代人类在离开非洲前往欧亚大陆时适应新环境。
“ By analysing the bits of Neanderthal DNA that remain in modern human genomes, we discovered a striking trend,” said John Capra, an epidemiologist at the University of California in San Francisco. Many of them affected genes that govern body clocks in modern humans, he said, in most cases increasing propensity to be a morning person.
“通过分析现代人类基因组中保留的尼安德特人 DNA 片段，我们发现了一个惊人的趋势，”旧金山加利福尼亚大学的流行病学家约翰·卡普拉表示。他表示其中许多片段影响了现代人类控制生物钟的基因，在大多数情况下增加了早起的倾向。
Waves of Homo sapiens migrated from Africa to Eurasia about 70,000 years ago. On arrival, they encountered the Neanderthals, who had already adapted to life in the colder climate, having occupied the territory hundreds of thousands of years earlier. Thanks to interbreeding between the groups, humans alive today carry up to 4% of Neanderthal DNA, including genes linked to skin pigmentation, hair, fat and immunity.
大约七万年前，一波又一波的智人从非洲迁徙到欧亚大陆。抵达后，他们遇到了尼安德特人，尼安德特人已经适应了寒冷气候的生活，并在数十万年前占领了这片土地。由于不同群体之间的杂交，今天的人类携带着高达4%的尼安德特人 DNA，其中包括与皮肤色素沉着、毛发、脂肪和免疫力相关的基因。
Capra and his colleagues analysed DNA from modern humans and Neanderthals and found different genetic variants were involved in the body clocks, or circadian rhythms, of the two groups. Since the ancestors of modern humans mated with Neanderthals, it was possible that some humans alive today carried the Neanderthal variants, they reasoned.
卡普拉与同事分析了现代人类和尼安德特人的 DNA，发现不同的基因变异与这两个群体的生物钟或昼夜节律有关。他们推断，由于现代人类的祖先与尼安德特人交配，今天活着的一些人类可能携带着尼安德特人的基因变种。
But being a morning person doesn’t require Neanderthal genes. Hundreds of different genes affect when people sleep and wake up, and there are plenty of environmental and cultural influences too. Overall, the Neanderthal genes have only a small impact.
但早起的人并不一定非得有尼安德特人的基因。数百种不同的基因会影响人们的睡眠和起床时间，此外还有大量的环境和文化影响。总体而言，尼安德特人基因的影响很小。
Prof Mark Maslin, of University College London, who was not involved in the study, said: “Now we have genetic evidence that some of us really are morning people. When humans evolved in tropical Africa, the day lengths were on average 12 hours long. Now hunter gatherers spend only 30% of their awake time collecting food, so 12 hours is loads of time. But the further north you go, the shorter and shorter the days get in winter when food is particularly scarce, so it makes sense for Neanderthals and humans to start collecting food as soon as there is any light to work by.”
伦敦大学学院的马克·马斯林教授没有参与这项研究，他表示：“现在我们有基因证据表明我们中有一些人确实是早起的人。当人类在热带非洲进化时，白天的长度平均为12小时。现在的狩猎采集者只用30%的清醒时间来收集食物，所以12个小时已经很长了。但越往北走，冬季的白天就越短，食物特别稀缺，因此对于尼安德特人和智人来说，只要天一亮就得赶紧开始收集食物了。”
