Tres L L
Arch Androl. 1979 Mar;2(2):101-7. doi: 10.3109/01485017908987300.
The pairing mechanism of the XY bivalent, the possibility of crossing-over between X and Y chromosomes during meiotic prophase, and the location of the H-Y locus are of interest with regard to genetic control mechanisms, male gametogenesis, and testicular organization. A whole-mount electron microscope technique has permitted the study of a large number of mouse and hamster spermatocytes to evaluate the spatial relationship of sex chromosomes and autosomes. X and Y chromosomes showed a transient, extensive side-by-side pairing segment along most of the length of the Y chromosome. This extensive pairing segment may cause genetic exchange between X and Y chromosomes. The finding of a small unpaired paracentromeric region of the Y chromosome could be related to a locus of totally sex-linked gene(s) that determine the development of the testis from the undifferentiated embryonic gonad.
XY二价体的配对机制、减数分裂前期X和Y染色体之间发生交叉互换的可能性以及H-Y基因座的位置，在遗传控制机制、雄性配子发生和睾丸组织方面备受关注。一种整装电子显微镜技术使得对大量小鼠和仓鼠精母细胞进行研究成为可能，以评估性染色体和常染色体的空间关系。X和Y染色体沿着Y染色体的大部分长度显示出一个短暂的、广泛的并排配对区段。这个广泛的配对区段可能会导致X和Y染色体之间发生基因交换。Y染色体上一个小的未配对的近着丝粒区域的发现，可能与一个完全性连锁基因座有关，该基因座决定了未分化的胚胎性腺发育为睾丸。
