小鼠精母细胞粗线期染色体SC长度和组型研究

Studies of Synaptonemal Complex Karyotype and their Length Changes during Pachytene in Mouse Spermatocytes

用整装微铺开和银染技术，在电镜下分析测量了３２个小鼠精母细胞粗线期染色体的联会复合体（ＳＣ）长度。１９个常染色体ＳＣ的总长度平均为１４７．８μｍ，ｘ、ｙ染色体轴平均长度分别为１２．５和５．４μｍ。处于粗线期不同阶段的ＳＣ长度变化较大，中粗线期与早晚粗线期ＳＣ长度的差异最大可达２倍以上，但它们的相对长度则比较稳定。粗线期ＳＣ长度约是有丝分裂中期染色体的３倍，两者具有很好的相关性（ｒ＝０．９９６）。ｘ、ｙ染色体行为落后于常染色体，配对始于早粗线期，完成于中粗线期。配对部分仅占ｘ染色体的１／１７和ｙ染色体的１／７。我们发现了一个ｘ＊ｙｙ三体，在这个三体中，其中一条ｙ染色体与ｘ染色体有较大的配对区，约占这条ｙ染色体总长的１／２，这有别于其他正常的ｘ·ｙ配对．

Using whole-mount,surface-spreading technique,synaptonemal complex karyotype and their lengthchanges during pachytene in mouse(Mus musculus)spermatocytes were analyzed by electron microscope。 Themean of total length of 19 autosomal SC is 147.8μm,and the lengths of x and y axes in 12.5μm and 4μm re-spectively。 The total length of the pachytene SC in three times that of metaphase chromosome。 Correlationanalysis showed that the length of SC was strikingly correlated with that of the metaphase chromosome(r=0. 996). The x-y pairing begins in early pachytene stage。 The paired part of x and y chromosomes is only 1/17of the length of the x and 1/7 of that of the y, but in xyy trisome, one of the two y chromosomes has greaterpairing region with the x chromosome,about 1/2 of its length。