家鸡联会复合体的亚显微结构分析

ELECTRON MICROSCOPY OF THE SYNAPTONEMAL COMPLEX IN SPERMATOCYTES AND OOCYTES OF GALLUS DOMESTICUS

本文以表面铺展——硝酸银染色技术,对家鸡的联会复合体(Syneptonemal Complex,SC)作亚显微结构分析。根据对10个精母细胞和10个卵母细胞SC的测量结果,绘制组型图。发现雌雄家鸡的常染色体的SC组型相同。在精母细胞中,性染色体(ZZ)的行为与常染色体相似。在卵母细胞中,性染色体ZW的长度不同,长轴为Z,短轴为W,两者之间只有部分配对,形成SC。从早粗线期到晚粗线期,由同源配对调整为非同源配对。另外,在一只雌鸡中,第一次观察到,有些细胞的常染色体能正常配对,而性染色体完全不配对的现象。

Surface-spreading and silver-stained preparation of spermatocytes and oocytes of chi-cken (Gallus domesticus) have been analyzed by electron microscopy. The chromosome number of Gallus domesticus is 78 and the sex determining mechanism is ZZ for males and ZW for females. An idogram of the synaptonemal complex karyotypes of male and female has been constructed from the data of ten spermatocytes andoocytes. There is no obvious difference in morphology of autosome pairing between spermatocytes and oocytes during meiotic prophase. In testicular meiotic cells, the synaptonema! complex of the Z chromosome is identical to that of the autosomes. In ovarian meiotic cells, SC is formed by two axes of different length and Z axis is longer than W's. The Z axis shortens markedly from early to late-pachytene and becomes thicker than the lateral elements of SCs. In the paired region, the Z axis forms mosy of the twists around a W axis, suggesting some extent of non-homologous pairing between the Z and W chromosomes in this region. In other case synaptic anomalies of sex chromosomes have been observed at pachytene in some cells of a female chick.