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 X*Y 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*XOfemales. Estimates of F1 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.

Low mitochondrial DNA variation and recent colonization of Scandinavia by the wood lemming Myopus schisticolor

“…1995). Methods of trapping wood lemmings and the sampling design were described earlier (Gileva & Fedorov 1991;Fredga et ul. 1993).…”

Genetic differentiation among populations of Myopus schisticolor (the wood lemming) — isozyme variation

“…The methods of lemming trapping and the design of the field study were described earlier (Gileva & Fedorov, 1991;Bondrup-Neilsen et a!., 1993).…”

Long-term stability of allozyme frequencies in a wood lemming, Myopus schisticolor, population with a biased sex ratio and density fluctuations

“…First it was hypothesized that the female biased sex ratio is maintained by inbreeding, especially when the population density is low (Maynard Smith and Stenseth, 1978;Stenseth, 1978). However, isozyme studies showed that wood lemming populations are generally in HardyWeinberg equilibrium (HWE) (Fedorov, 1990(Fedorov, , 1991(Fedorov, , 1993Gileva and Fedorov, 1991;Fredga et al, 1993) indicating random mating.…”