安徽沿江地区4种蛇的染色体组型、C带和Ag-NORs研究

STUDIES ON THE KARYOTYPE, C-BANDS AND Ag-NORs OF FOUR SPECIES OF SNAKES FROM THE AREAS ALONG THE YANGTZE RIVER IN ANHUI

本文报道游蛇亚科４种蛇的核型、Ｃ带和ＡｇＮＯＲｓ，结果：黄链蛇２ｎ＝４６．虎斑游蛇２ｎ＝４０，第４号染色体（Ｎｏ．４）有随体．鸟梢蛇和紫灰锦蛇２ｎ＝３６，鸟梢蛇的Ｎｏ．５短臂近着丝粒区有一次缢痕．虎斑游蛇Ｎｏ．５为性染色体，其余３种的性染色体为Ｎｏ．４．这４种蛇均为ＡＦ＝５０；Ｃ带型的种属性特征明显，其中紫灰锦蛇的端粒型Ｃ带特别发育，其余三种以着丝粒Ｃ带较发达．黄链蛇、虎斑游蛇和紫灰锦蛇的Ｗ染色体Ｃ带正染呈现整条异染色质化；银染结果４种蛇均只显示一对ＮＯＲｓ，但其分布不同，其中虎斑游蛇ＮＯＲｓ呈异态现象．文章讨论了核型的演化和次缢痕。

The karyotypes, C bands and Ag NORs of four species of snakes from the areas along the Yangtze River in Anhui are reported in this paper. The results indicate Dinodon flavozonatum 2 n =46. Rhabdophis tigrinus lateralis 2 n =40, with the satellite in chromosome No.4. Zaocys dhumnades and Elaphe porphyracea nigrofaciata have 2 n =36, with the secondary constriction in the percentric region of the short arm of chromosome No.5 in Z. dhumnades . The chromosome No.5 are sex chromosomes in R. t. lateralis , while those of other three snakes are chromosome No.4. All the four species of snakes have AF=50; The C bands of E. p. nigrofasciata are basically constant, mainly located at the end of macro chromosomes, while C bands of other three snakes mainly located in the centromeric positions of chromosomes, but there are noticealbe distinction between the three species. The heterochromatinization of W chromosome of D. flavozonatum R.t. lateralis and E. p. nigrofasciata is found; Only one homologous pair of NORs are found in any of the four species. But the positions of NORs are different among the four species, and the heteromorphism of NORs is observed in R. t. lateralis . The evolutionary trend and the relationship of the secondary constriction, Ag stained NORs and C bands of the snakes are discussed.