斜鳞蛇核型高分辨显带及减数分裂的观察

STUDY ON THE KARYOTYPE,HIGH RESOLUTION BANDING MEIOSIS OF Pseudoxenodon macrops (SNAKE)

本文报道了斜鳞蛇（Ｐｓｅｕｄｏｘｅｎｏｄｏｎｍａｃｒｏｐｓ）的核型和银带。二倍体数目２ｎ＝３６，其中包括８对大染色体（６对中着丝粒染色体，２对亚中着丝粒染色体）和１０对小染色体。其核仁组织区（ＮＯＲｓ）位于第１对小染色体末端。并采用ＴｄＲ－ＢｒｄＵ处理方法，显示斜鳞蛇复制带，实验证明，用大剂量的胸腺嘧啶核苷（ＴｄＲ）阻断细胞周期，再以ＢｒｄＵ渗入Ｓ期细胞中复制的染色体区域，并显示带纹。同时还对斜鳞蛇的减数分裂进行了观察。

The mitosis and meiosis of Pseudoxenodon macrops had been investigated,using conventional Giemsa and silver staining and BrdU induced condensation inhibition.The diploid number is 2n= 36 with 16 macro-and 20 microchromosomes (macro autosomes are 10 metacentric and 6 submetacentric). Silver staining NORs were localized on the.microchromosomes pair No. 1 .The high resoluting banding of Pseudoxenodon macrops is sucessfully made by blocking the cycle of cell with large dosage of TdR and incoporating BrdU into the replicating chromosomal DNA during synthesis phase. These banding patterns allow for the first time a precise identification of all macro-chromosomes and the analysis of the patterns of replication in the various stages of Sphase in snake. This information could clarify the taxonomic and phylogenetic relationships among certain familes of colubrinae as well as the evolutionary relationships within certain families.