超级名模和影视红星如何保持纤细苗条的身材一直是人们津津乐道的话题，多数猜测这些公众人物完美的体型是严格节食的结果，但是遗传学家最新的研究成果给出全新的答案。遗传学家发现了一种“瘦体”基因，这种基因是由家族里母亲的身上遗传到孩子的体内的。
“瘦体”基因是由英国牛津大学一个由乔-普鲁顿教授主持的研究小组发现的，这是他们进行线性体DNA研究的一个内延扩展部分。牛津大学的研究人员在对161名母亲和她们20岁的子女的DNA进行了检测，在这之前研究人员还对他们的体质指数进行了比较，体质指数是用来衡量体重是否标准的重要尺度，结果发现，携带“瘦体”基因的女性平均的体质指数为21.9，而没有携带这种基因的女性平均体质指数为23.5。研究人员表示，体内携带这种基因的女性比没有携带此类基因的女性更瘦一些，而且携带“瘦体”基因的女性的孩子更容易从母亲那里遗传到这种基因。普鲁顿教授认为携带“瘦体”基因的人体内新陈代谢进行的更快，使他们体内的脂肪消耗的更快，而不会贮存在体内。据她的估计，只有大约8%的人携带这种基因。
研究结果显示，由于“瘦体”基因是从母亲那里遗传的，因此父亲体形对子女体形的形成不会起到太大的作用，即使父亲大腹翩翩，做子女的也不用有丝毫担心，不过父亲的某些基因可能会对子女上了年纪后的体重产生一定的影响。普鲁顿教授表示，“瘦体”基因之所以只能从母亲那里遗传，是因为线性体DNA只能由母亲遗传的结果，这也意味着父亲的基因在后代体形的形成过程不起太大的作用。
这个研究成果或许可以解释世界上一些极富魅力的女性可以轻而易举地保持她们优美的体型，比如，以体型纤细著称的超级名模纳奥米-坎贝尔和凯特-摩斯两人的母亲也都很苗条，美国超级名模杰瑞-夏尔就明显把她“瘦体”基因遗传给她同样在娱乐圈崭露头角的女儿伊丽莎白贾格尔，电视红星珍西摩尔也把同样的基因遗传给了她同样也是位演员的女儿凯特-弗林。
目前，人们指责一些超级模特为满足职业的要求以节食来保持体形给年轻的女孩造成了不良的影响，因此时尚专家这个与以往不同的科学解释十分欢迎，他们表示，这些公众明星与她们的母亲出现在公众场合时，人们就会发现她们母女之间体形的相似之处，不过如果人们看到明星的母亲年轻时的样子，就会更加吃惊。
普鲁顿教授表示，研究的结果显示出母亲和她们20岁的子女在体形趋于苗条之间有着紧密的联系，但是目前还不清楚这种基因是如何发挥作用的，对线性体DNA的研究表明这种基因是由母亲遗传给子女的。先前的研究结果显示，携带“瘦体”基因的女性生育的孩子体重更轻，而且携带此类基因的人在上年纪后更易患上2类糖尿病，特别是摄入过多脂肪时。普鲁顿教授表示，尽管“瘦体”基因能够使脂肪不易贮存体内，但可能会导致子女上了年纪后身体产生其它问题。她表示，这种基因出现在婴儿、儿童和年轻人体内时，能够使他们的体形变得更瘦，但是在他们长到60岁时就不知道会造成什么后果了。
英国敦提大学的一位研究肥胖症的专家表示，这项研究成果为基因对人体体重的影响提供了新的证据，这说明线性体DNA对人体能量的平衡起着十分重要的作用。
THEY may not be starving themselves on a lettuce diet after all. The real secret behind stick-thin supermodels and actresses has been revealed to be their mothers.
Geneticists have discovered a "thinness" gene that is passed down through families from mothers to their children.
The researchers found that women carrying the gene were skinnier than those without it and that their children were also more likely to inherit their mother's slight build if they had the gene.
It may help explain how some of the world's most glamorous women are able to maintain their slimline figures so easily. Superslim models Naomi Campbell and Kate Moss both have skinny mothers. One of the original "supermodels", the statuesque Texan Jerry Hall, appears to have passed on a thinness gene to her daughter Elizabeth Jagger. TV star Jane Seymour appears to have done the same for her actress daughter Katie Flynn.
The researchers claim that because the gene is passed down maternally, fathers - regardless of the size of their beer belly - play little role in determining the body shape of their children, although other paternal factors may influence weight in later life.
The gene was identified by Dr Jo Poulton and her team at the genetics department of Oxford University inside stretches of genetic material responsible for metabolism known as mitochondrial DNA.
Poulton believes people with the gene may have a faster metabolism that allows them to get rid of fat rather than storing it. She estimates that around 8% of the population carry the gene.
"We demonstrated a significant association between the variant and thinness in both mothers and their 20-year-old offspring," said Poulton. "We don't fully understand the mechanisms yet but this mitochondrial DNA seems to pass the likelihood of thinness from mothers to their children. It may explain why families can have several generations of very thin people."
The current generation of top models have been accused of starving themselves into the shape required for the catwalk and providing poor role models for teenage girls. Style experts said they would welcome a different scientific explanation for their look. "Often when you see celebrities with their mothers in public you can see the similarities between their bodies and it is even more striking when you see how their mothers used to look," said Leoni Roberts, from the Federation of Image Consultants. "Naomi Campbell springs to mind as she and her mother, who was a dancer, look so similar they could be sisters.
Former model Freda Bartlet, 40, from Glasgow, believes the research may explain why the women in her family have such a slim build.
Her daughter Haley, 16, has a 23 inch waist and works for Glasgow-based modelling agency Model Team. "When I was Haley's age I used to eat constantly and never put on any weight as I had such a fast metabolism," said Bartlet. "I weighed about seven and a half stone. My mother was exactly the same and now Haley is taking after us. She often wears some of my clothes from when I was younger."
The Oxford study examined the DNA of 161 white, middle-class mothers and their 20-year-old children before comparing the results against their Body Mass Index, a measure of body fat using weight and height. Poulton found that women carrying the gene had an average BMI of 21.9kg/m2 compared with 23.5kg/m2 in those who lacked it.
Earlier research showed that women who carried the gene also gave birth to smaller babies. But Poulton warned that while the gene may protect against getting fat, it may cause other problems in later life.
She said: "When the gene is present in babies, children and young people it seems to confer a thinner physique but we don't yet know what happens when those people get into their sixties.
"Previous research has also found people with this gene have a higher chance of developing type 2 diabetes in later life, particularly if they eat a high fat diet. We think it might be something known as a 'thrifty gene', which was advantageous when food was scarce by allowing more efficient use of food. It can cause problems now food is so abundant all the time."
Poulton also explains that the gene can only be passed down by mothers to their children because mitochondrial DNA is usually only inherited maternally. It means that a father's genetic make-up may play little part in the body-shape of their offspring.
Dr Colin Palmer, an expert on obesity at Dundee University, said the research shed new light on the understanding of how genetics can effect a person's weight. He said: "There have been genes identified for obesity and they are to do with eating behaviour and regulation of appetite. This research seems to come at it from the other angle, but it would make sense as mitochondrial DNA is totally vital to energy balance and how the body adapts to overeating."
A spokesman for the Eating Disorder Association added: "We welcome any research that helps us understand the reasons that lead to people developing eating disorders."
This article: http://news.scotsman.com/scitech.cfm?id=2349862005
