Chromosome Variation in Two Populations of Xenochrophis piscator Schn. from North and South India (Serpentes, Colubridae)

抄録

The karyotypes in Agra (North India) and Quilon (South India) populations of Xenochrophis piscator are 8 VS+2 rods+28 dots and 10 VS+6 rods+20 dots, respectively. There are less important differences in mitotic and meiotic details too. A hypothetical mechanism has been envisaged whereby, such changed karyotypes with distinct polymorphism arose. It is felt that within Agra karyotype of Xenochrophis certain structural changes took place either because of advantageous mutation or cumulative effect of countless generations, subsequent fusions led to the evolution of Quilon karyotype. Analysis of variance of chiasma frequency in both the populations reveals that inspite of chromosomal repatterning recombination index has not been altered much. The revision of systematics data in this species seems necessary.