Evolution of microsatellite alleles in four species of mice (genus Apodemus)

Kateryna D. Makova,* Anton Nekrutenko,* Robert J. Baker

Department of Biological Sciences, Texas tech University, Lubbock, TX 79409 USA

* Present address: Department of Ecology and Evolution, The University of Chicago, Chicago, IL 60637 USA

Abstract. Microsatellite length variation was investigated at a highly variable microsatellite locus in four species of Apodemus. Information obtained from microsatellite allele sequences was contrasted with allele sizes, which included 18 electromorphs. Additional analysis of a 400-bp unique sequence in the flanking region identified 26 different haplotype sequences or “true” alleles in the sample. The molecular mechanisms, namely, (1) addition/deletion of repeats, (2) substitution and indels in the flanking region, and (3) mutations interrupting the repeat, contributed to the generation of allelic variation. Size homoplasy can be inferred for alleles with populations, from different populations on the same species, and from different species. We propose that microsatellite flanking sequences may be informative markers for investigating mutation process in microsatellite repeats as well as phylogenetic relationships among alleles, populations, and species.