Genetic structure of populations of Calomys laucha (Muridae, Sigmodontinae) from central Argentina

CHIAPPERO, M.B.; BLANCO, A.; CALDERÓN, G.E.; SABATTINI, M.S.; GARDENAL, C.N.

BIOCHEMICAL SYSTEMATICS AND ECOLOGY

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2002 vol. 30 p. 1023 - 1036

0305-1978

The genetic structure of populations of the Sigmodontinae rodentCalomys laucha was studied by means of allozyme electrophoresis. This highly opportunistic species is found preferablyin periodically perturbed habitats of crop fields in central Argentina, where it can attain veryhigh densities. A total of 17 enzymatic proteins assayed gave information on 25 loci; onlyfour were monomorphic in the seven populations studied. Levels of genetic variability (Hofrom 0.144 to 0.171; P95% from 44% to 56%) were higher than mean values reported formammals and rodents. These high levels of heterozygosity could be maintained by large populations that do not experience great fluctuations in size, or by a social structure consistent inmany small breeding groups that are formed and dissappear every breeding season. Geneticdifferentiation at a macrogeographical scale (θ=0.018) was low but statistically significant,and showed no correlation with geographic distance between pairs of populations. The patternof population differentiation found is compatible with a relatively recent range expansion