Researchers studying how genes control animal behavior have had to deal with many uncertainties. In the first place, most behaviors are governed by more than one gene, and until recently geneticists had no method for identifying the multiple genes involved. In addition, even when a single gene is found to control a behavior, researchers in different fields do not necessarily agree that it is a “behavioral gene.Neuroscientists, whose interest in genetic research is to understand the nervous system (which generates behavior), define the term broadly. But ethologists ― specialists in animal behavior― are interested in evolution, so they define the term narrowly. They insist that mutations in a behavioral gene must alter a specific normal behavior and not merely make the organism ill,so that the genetically induced behavioral change will provide variation that natural selection can act upon, possibly leading to the evolution of a new species. For example, in the fruit fly, researchers have identified the gene Shaker, mutations in which cause flies to shake violently under anesthesia. Since shaking is not healthy, ethologists do not consider Shaker a behavioral gene. In contrast, ethologists do consider the gene period (per), which controls the fruit fly’s circadian (24 hour) rhythm, a behavioral gene because files with mutated per genes are healthy, they simply have different rhythms.
大家请看，这个For example（论据）并不能支持论点，前面说not merely makes organism ill，意思是不仅仅是对生物体有害~~而举出来的例子是说当某个行为是不健康的，就不能被视为behavioral gene~~这个例子怎么能证明前面的观点呢？还是我理解错了？反正看的时候特纠结，求NN指导啊~ | 
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发表于 2011-10-5 14:55:23
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