A cytogenetic analysis of meiotic drive in the mosquito, Aedes aegypti (L.)
A cytogenetic analysis of meiotic drive in the mosquito, Aedes aegypti (L.)
复制标题
埃及伊蚊减数分裂驱动的细胞遗传学分析
作者：
M. Newton;R. Wood;D. I. Southern
吉姆萨 C 显带技术表明，埃及伊蚊 (L.) 的减数分裂驱动与雄性减数分裂期间 X 染色体的优先等染色单体断裂有关。这些断裂至少在后期 I 之前一直保持开放状态，并且由于受影响的细胞范围与 X 染色体对 Distorter 基因的敏感性成正比，因此有人认为它们与扭曲男性中发现的精子数量减少直接相关。这种减少被认为是由于带有X的精子细胞比带有Y的精子细胞变性更多，但也可能产生一些无功能的带有X的精子。染色体断裂几乎完全局限于四个位点，两个位点邻近着丝粒，一个位点紧邻居带，另一个位点位于无带臂的中心附近。尽管前三个位于不发生交换的区域内，但在交叉臂中比在没有染色单体交换的臂中更频繁地发生断裂。
Meiotic drive in Aedes aegypti (L.) is shown by a Giemsa C-banding technique to be associated with preferential isochromatid breakage of the X chromosome during male meiosis. These breaks remain open at least until anaphase-I and, since the range of cells affected is proportional to the sensitivity of the X chromosome to the Distorter gene, it is argued that they are directly related to the decreased number of spermatozoa found in distorting males. This reduction is considered to be attributable to the degeneration of more X- than Y-bearing spermatids but it is probable that some non-functional X-bearing spermatozoa are also produced. Chromosome breakage is almost completely confined to four sites, two adjacent to the centromere, one just proximal to the intercalary band and another about the centre of the unbanded arm. Although the first three of these lie within a region in which crossing-over does not take place, fragmentation occurs more frequently in a chiasmate arm than in one devoid of chromatid exchange.