主页 > 生命科学 >
【bio-news】肥胖基因与消瘦基因有何不同
How fat genes differ from thin ones
Resequencing effort unpicks genetics of body extremes.
Erika Check
Researchers have used a new technique to hunt for rare genetic quirks that explain why some people are extremely fat or very thin.
The researchers, led by Len Pennacchio of the Lawrence Berkeley National Laboratory in California, studied 757 Canadians from Ottawa. Half of the participants were chosen because they were fatter than 95 of the general population for their height: on average they weighed 125 kilograms. The other half was thinner than 90% of the population, with a mean weight of 57 kilograms.
The team examined 58 genes known to be related to obesity, appetite, or the conversion of food into energy, in every participant. They looked for tiny differences between people in the series of chemical building blocks that make up each gene. This technique, called medical sequencing or resequencing, aims to discover rare genetic variations that may subtly influence particular traits — including body size.
Most previous genetic trawls have focused on using the HapMap — a catalogue of common genetic variants shared by most people with a certain disease. Resequencing is different, as it looks for genetic quirks that are unique to just a few individuals. Resequencing studies have been used to find variations that may cause cancer1 and differences in cholesterol2, whereas HapMap studies have been used to hunt for more common variations that contribute to a range of conditions, including diabetes (see 'Broad sweep of genome zeroes in on diabetes').
Small pieces of the puzzle
Pennacchio's team found 1,074 genetic variants in the sequenced genes, they report in the American Journal of Human Genetics3. Most of these variants were rare, meaning they were found in less than 1% of the study participants. The fat participants had significantly more variation in the genes known to be linked to severe obesity. But when the team looked for the same rare variants in family members of the affected participants, they couldn't link the genetic difference directly to body size. So each variant on its own isn't enough on its own to make a person fat or thin.
"Obesity is such a complex condition — it's not a black-and-white thing — so it doesn't mean these genes might not contribute to weight differences, it just says they're not clearly causative on their own," Pennacchio says.
Scientists are unsure how much rare and common genetic variants contribute to disease, especially in complex disorders such as obesity, which are caused by multiple environmental and inherited factors. And it is proving hard to pin down — at least for now. Resequencing studies are more difficult and expensive than HapMap studies, so fewer scientists have done them.
"We could show that there are rare variants that have a significant difference between obese and lean subjects, but even with the amount of sequencing we've done, we can only scratch the surface," Pennacchio says.
As the cost of resequencing studies drops, Pennacchio predicts that the problem will be cracked. "This is going to be a big growth area for the field."
Visit our newsblog to read and post comments about this story.
References
Greenman C., et al. Nature, 446 . 153 - 158 (2007). | Article |
Cohen J. C., et al. Science, 305 . 869 - 872 (2004). | Article | PubMed | ISI | ChemPort |
Ahituv N., et al. American Journal of Human Genetics., 80 . 779 - 791 (2007). | PDF |
http://www.nature.com/news/2007/070312/full/070312-9.html 本人已认领该文编译，48小时后若未提交译文，请其他战友自由认领。 Published online: 16 March 2007;
网上发表时间：2007－3－16
How fat genes differ from thin ones
肥胖基因与消瘦基因有何不同
Resequencing effort unpicks genetics of body extremes.
Erika Check
基因测序的努力揭开了人体遗传学的奥秘
Erika Check
Researchers have used a new technique to hunt for rare genetic quirks that explain why some people are extremely fat or very thin.
研究者们使用了一种新的技术来探求罕见基因的特性，从而能够解释有些人非常胖而有些人则非常瘦。
The researchers, led by Len Pennacchio of the Lawrence Berkeley National Laboratory in California, studied 757 Canadians from Ottawa. Half of the participants were chosen because they were fatter than 95 of the general population for their height: on average they weighed 125 kilograms. The other half was thinner than 90% of the population, with a mean weight of 57 kilograms.
加利福尼亚州劳伦斯伯克利国家实验室的Len Pennacchio所领导的研究者们研究了757名来自渥太华的加拿大人。其中一半被选择是因为他们比95％的一般人群要胖：他们的平均体重是125公斤。而另外一半瘦于90％的一般人群，他们的平均体重是57公斤。
阅读本文的人还阅读：
作者:admin@医学,生命科学 2011-09-19 05:12
医学,生命科学网