VOA慢速英语2009年-Health Report - Researchers Link Gene to N

This is the VOA Special English Health Report.

The next time you think about going without sleep, consider this: Laboratory animals that are kept awake for long periods of time ... die.

Yet sleep scientist Ying-Hui Fu at the University of California, San Francisco, says little is known about the basic need for sleep.

YING-HUI FU: "We do not why some humans need more sleep; why some humans need less sleep; why, when we do not sleep, we do not function well. We just do not know much about sleep at all."

But here is something that scientists now know: A team led by Professor Fu has reported the first genetic² link to how much sleep we need.

The team was looking for a natural clock in the body that controls sleep and wakefulness. What they found was a genetic abnormality. People who have this mutation³ need less sleep than others.

But keep in mind that the scientists say this mutated gene¹ may be rare. The study involved two members of an extended family. They did fine on just six hours of sleep a day. Studies have shown that over time, most humans need eight to eight and a half hours of sleep for the best health.

To test their theories, the scientists genetically⁴ engineered the mutation in mice. The mice with the mutation needed less sleep than normal mice. They were also more active even after being kept awake.

The study appears in the journal Science. The researchers will continue to study the mice to test whether the gene is related to other medical conditions. And they will study whether it is involving in controlling sleep quantity alone, or also what scientists call the "wakefulness-behavioral drive." This drive is important for getting food, shelter and mates.

How you sleep can be as important as how much you sleep -- especially for newborn babies. A new report says images in parenting and women's magazines may send the wrong message about how to put babies to bed.

The study found that more than one-third of the pictures in women's magazines showed babies in unsafe sleep positions. They showed babies sleeping on their sides or stomachs. Also, only a third of the pictures showed sleep environments considered safe by the American Academy of Pediatrics.

The academy says babies should sleep on their backs. It says they should be placed on a separate sleep surface from their parents, without blankets, pillows or other soft bedding. These guidelines are credited with reducing cases of sudden infant death syndrome⁵ in the United States.

And that's the VOA Special English Health Report, written by Caty Weaver⁶ with Jessica Berman. For more health news, go to voaspecialenglish.com. I'm Mario Ritter.

1 gene   

n.遗传因子，基因

参考例句：

• A single gene may have many effects.单一基因可能具有很多种效应。
• The targeting of gene therapy has been paid close attention.其中基因治疗的靶向性是值得密切关注的问题之一。

2 genetic   

adj.遗传的，遗传学的

参考例句：

• It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。
• Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。

3 mutation   

n.变化，变异，转变

参考例句：

• People who have this mutation need less sleep than others.有这种突变的人需要的睡眠比其他人少。
• So far the discussion has centered entirely around mutation in the strict sense.到目前为止，严格来讲，讨论完全集中于围绕突变问题上。

4 genetically   

adv.遗传上

参考例句：

• All the bees in the colony are genetically related. 同一群体的蜜蜂都有亲缘关系。
• Genetically modified foods have already arrived on American dinner tables. 经基因改造加工过的食物已端上了美国人的餐桌。 来自英汉非文学 - 生命科学 - 基因与食物

5 syndrome   

n.综合病症；并存特性

参考例句：

• The Institute says that an unidentified virus is to blame for the syndrome. 该研究所表示,引起这种综合症的是一种尚未确认的病毒。
• Results indicated that 11 fetuses had Down syndrome. 结果表明有11个胎儿患有唐氏综合征。

6 weaver   

n.织布工；编织者

参考例句：

• She was a fast weaver and the cloth was very good.她织布织得很快，而且布的质量很好。
• The eager weaver did not notice my confusion.热心的纺织工人没有注意到我的狼狈相。