crownclown
2011-9-16 05:39 AM
Crossing over 是在 meiosis. 在那时 exchanging of the genetic materials to create a genetic variation in the following generation. Synapsis 是当homologous chromosomes 靠近在一起 arrange together and formed tetrad or bivalent. 在meiosis 1, homologous chromosome considered as 1 chromosome 而在 meiosis 2, 分开后的 homologous chromosomes 变成 sister chromatids 而一个 sister chromatid 算一个 chromosome. X and Y considered as 1 chromosome each. 应该是这样吧？
谢谢你~ 
