File(s) stored somewhere else

Please note: Linked content is NOT stored on Carnegie Mellon University and we can't guarantee its availability, quality, security or accept any liability.

Impact of migration and fitness on the stability of lethal t-haplotype polymorphism in Mus musculus: a computer study.

journal contribution
posted on 01.04.1997, 00:00 authored by Dannie Durand, Kristin Ardlie, Linda Buttel, Simon A. Levin, Lee M. Silver

The t-haplotype is a chromosomal region in Mus musculus characterized by meiotic drive such that heterozygous males transmit t-bearing chromosomes to roughly 90% of their offspring. Most naturally occurring t-haplotypes express a recessive embryonic lethality, preventing fixation of the t-haplotype. Surprisingly, the t-haplotype occurs in nature as a persistent, low-frequency polymorphism. Early modeling studies led LEWONTIN to hypothesize that this low level polymorphism results from a balance between genetic drift in small demes and interdemic migration. Here, we show that while combination of deme size and migration rate that predict natural t-haplotype frequencies exist, the range of such values is too narrow to be biologically plausible, suggesting that small deme size and interdemic migration alone do not explain the observed t-haplotype frequencies. In response, we tested other factors that might explain the observed t-polymorphism. Two led to biologically plausible models: substantially reduced heterozygous fitness and reduced meiotic drive. This raises the question whether these phenomena occur in nature. Our data suggest an alternative explanation: there is no stable, low-level t-polymorphism. Rather wild populations are in one of two stable states characterized by extinction of the t-haplotype and a high t-haplotype frequency, respectively, or in transition between the two.

History

Date

01/04/1997