蚜虫和蝗虫的性别决定初探

XA型生物性别决定机制的特点:蚜虫的X染色体含X基因的数量小于常染色体组合的Y基因,为0.6-0.8;蝗虫的X染色体与常染色体含X基因与Y基因的数量相同,为1.0;X染色体含的X基因全都能在性别决定中起作用,会是有效性基因;常染色体组则随各种性型的X染色体与常染色体组的数量关系不同,所含的Y基因有的在性别决定中起作用,有的在性别决定中不起作用,有有效性基因和无效性基因之别。由此,决定了蚜虫须经历有性和无性两个世代,以有性和无性两种生殖来完成世代交替,靠营群居生活才能进行繁衍生息;蝗虫不再须经历有性有无性两个世代,只以有性生殖来完成世代交替,营独栖生活也能进行繁衍生自。

Analysis of Sex - determing Factors of Aphid and Locust

It describes the characters of the sex - detering system of XA creature as following. For an aphid , the amount of its X genes (0.6-0.8)of the X chromosome is smaller than that of its Y genes of the euchromosome , but they are the same for a locust(1.0). All X genes of X chromosome are effective. They can work during the sex - determing Process. However , some of the Y genes of its euchromosome can be effective , some not. That depends on the defference between the amounts of the X chromosome and euchromosome. The character determines that an aphid mush have two generations: Sex and sexless-ness . Only with the two generations , can the aphid spring its off springs. So , they must live in groups. The locusts need not to live through the two generations , They spring their off springs only with sex generation , and they can reproduce themselves even live alone.