颈棱蛇核型和Ag－NORs的研究

本文研究了云南产颈棱蛇的核型和Ａｇ－ＮＯＲｓ。其Ｚｎ＝４６，由８对大染色体和１５对小染色体组成，大染色体中Ｎｏ．６、８为亚中着丝粒染色体，其余均为端或亚端着丝粒染色体。在Ｎｏ．２的末端有一明显的次缢痕，常常只在一条同源染色体上可见。第４对大型染色体为性染色体，雌性为ＺＷ型，其中Ｚ染色体较大，而Ｗ染色体长度仅为Ｚ染色体的三分之二。一对核仁组织者（ＮＯＲｓ）位于Ｎｏ．２末端，其位置与次缢痕位置相对应。文中还对颈棱蛇的分类和进化进行了讨论。

A STUDY ON THE KARYOTYPE AND Ag-NORs OF YUNNAN Macropisthodon rudis(Reptilia:Colubridae)

The karyotype and Ag-NORs of Macropisthodon rudis from Kunming,Yunnan Province,were examined and characterized.It had a diploid number of 46 with 16 macro and 30 micro-chromosomes.Among the 8 macrochromosomes,Nos.6 and 8 were submetacentric,and the others telocentric or subtelocentric. A secondary constriction was observed on the long arm of the second largest pair.The fourth largest pair were determined as the sex chromosomes.Z chromosome was large,and metacentric,while the W chromosome was two thirds as long as Z and submetacentric.Ag-NORs were localized on No.2,adhering to the secondary constriction.This result differs from a previous report of samples from Japan (Nakamura,1935).Implications of taxonomy and evolution of the results were also discussed.