Genetic distinctiveness of a village population of house mice: relevance to speciation and chromosomal evolution

Abstract

SUMMARYA population of house mice, Mus musculus domesticus, from the village of Migiondo was found to be genetically distinct from nearby populations in Upper Valtellina (Italian Alps). At the supernatant malic enzyme locus, Mod1, the only alleles found in Migiondo (c and n2) were virtually absent from the other populations in the valley, which were characterized by allele a. The extraordinary genetic distinctiveness of the Migiondo population is apparently the result of genetic drift, perhaps coupled with a founder event, and attests to the existence of nearly impenetrable geographic barriers around the village isolating it from other settlements only a few hundred metres away. The Mod1 features of the house mice in Migiondo are reminiscent of the characteristics of house mice on maritime islands. The genetic confirmation of the geographic isolation of Migiondo is of interest because there is evidence that this village may have been the site of recent speciation and extinction events. The data are also of significance given the phenomenal chromosomal variation in house mice from the vicinity of the Alps. It has frequently been proposed that genetic drift\founder events are of importance in the fixation of chromosomal rearrangements ; this study provides the first direct evidence for their occurrence in alpine mouse populations.

Complex Nature of the Genome in a Wine Spoilage Yeast, Dekkera bruxellensis

“…VOL. 8,2009 COMPLEX GENOME IN DEKKERA BRUXELLENSIS 1745 on May 10, 2018 by guest http://ec.asm.org/ isolate auxotrophic mutants in this yeast (our unpublished observations). However, our Southern analysis showed that all five gene probes hybridized to more than one chromosomal band in a majority of strains (Table 2 and Fig.…”

“…Only rarely do geographically separated populations, for example, Mus musculus (8,32), differ in the number and form of chromosomes. The mutability of the genome enhances the adaptability of the species, but it also decreases the viability of the new variant.…”

Linkage-Dependent Gene Flow in a House Mouse Chromosomal Hybrid Zone

“…Founder events and long-distance dispersal associated with colonization of empty habitat can also occur (Hauffe and Searle 1993). Allozyme data have highlighted the importance of these factors in Valtellina, with almost complete differentiation between one village (Migiondo) and the rest of the valley at the Mod1 locus (Fraguedakis-Tsolis et al 1997).…”

Microgeographical distribution of two chromosomal races of house mice in Tunisia: pattern and origin of habitat partitioning

“…Such premating isolating mechanisms may involve behavioural divergence in mating-signal systems, which are known to make a major contribution to genetic isolation between species (Butlin & Ritchie 1994). In the house mouse, discriminatory aggressiveness has been observed between chromosomal morphs in Scotland , and a case of reproductive isolation that may involve ethological barriers has been documented between Rb races in Italy (Capanna & Corti 1982;Fraguedakis-Tsolis et al 1997). Unravelling the respective contributions of these di¡erent traits to reproductive isolation between the two chromosomal races in Tunisia requires further genetic, ecological and behavioural studies.…”