Sex ratio, xy females and absence of inbreeding in a population of the wood lemming, myopus schisticolor lilljeborg, 1844

Abstract

In a Siberian population of the Wood Lemming a considerable excess of females has been observed for three subsequent years of low density. Female-biased sex ratio is associated with a high concentration of the X chromosome which induces the development of XY specimens as females. The frequency of XY females was noticeably higher than that expected at equilibrium under rAndom segregation of sex chromosomes in males And X*X° females. Estimates of Frs index were obtained from the frequencies of homozygotes And heterozygotes for the Idh-1 locus And for dimorphic chromosome No. 2. Apparently inbreeding does not contribute to the maintenance of the aberrant genetic system of sex determination in natural populations of Myopus schisticolor. © 1991 The Genetical Society of Great Britain.