轮虫并不普通,因为他们的繁殖方式是孤雌生殖。顾名思义,孤雌生殖群体全是雌性;如果没有接受和传递罕见基因突变,那么轮虫的雌性后代与母体是完全相同的。这使得轮虫成为十分方便的研究对象:人们对在个体生命期中,后天习得的特征与繁殖后代中的DNA突变并不相关这个观点存在争议。
Dr Watabe and his colleagues first looked at whether caloric restriction does, indeed, workits magic on rotifers. It does. Without it, as they report in Functional Ecology, their animalslived for an average of 8.8 days. With it they lived for 13.5 days. The intriguing result camewhen they did the same thing with the rotifers offspring. The daughters of those rotiferswhich had been fed as much as they could eat lived for 9.5 days if treated likewise and 14.4 if put on short commons. Those born ofcalorie-restricted mothers lived for 12.7 and 16.8 days respectively. Something, then, isbeing passed on that is having an effect down the generations.
渡边博士和他的同事第一次研究热量限制的机制是否对轮虫同样有效。确实有效。他们在《机能生态学》杂志上报道说,没有了热量限制,轮虫的平均生命期为13.5天。当它们对轮虫的后代采取了同样的热量限制后,得到了有趣的结果。轮虫的母系如果得到了饱和的食物量,它们那些也同样饱食的后代可以存活了9.5天,如果后代食物量减少,则可以活14.4天。那些诞生于热量限制的母系后代则在饱食和不饱食的情况下分别存活了12.7 和16.8天。那么,一定有某种物质通过上下代传递,对个体生命产生了影响。
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