导读：有些人每天睡9个小时，白天上班还是在犯困；有人只睡4、5个小时，却能全天精力充沛，效率超高。到底为什么会这样呢？研究人员说，是基因的问题。

Researchers recently discovered a gene that regulates the duration of sleep an individual needs. The new findings may explain why some people appear to have an internal alarm clock, and can wake up on their own. It may also explain why some people are light sleepers, able to operate on only a few hours of sleep.

研究人员最近发现了一种能够管理人们所需睡眠时间长短的基因。这一新发现或许能解释，为什么有些人好像有个内置的闹钟，总能自己定点醒来；而有的人每天只睡几个小时却依然精力充沛。

The research was conducted by members of the Ludwig Maximilians University (LMU) of Munich. The gene the team identified is called ABCC9 and has been nicknamed the "Thatcher gene" in honor of former British Prime Minister Margaret Thatcher, famous for needing as little as four hours of sleep a night.

该研究是由慕尼黑大学的研究人员进行的。他们发现的这个基因叫做ABCC9，后被人以前英国首相撒切尔夫人的名字命名，戏称为“撒切尔基因”，因为撒切尔夫人以睡眠时间少而著称，每天的睡眠时间只有四个小时。

Researchers discovered that people who had two copies of one common variant of ABCC9 slept for "significantly shorter" periods than people with two copies of another version.

研究人员发现，体内有两组ABCC9基因变种的人比其他人的睡眠时间“明显缩短”。