Phylogeographic structure in the subterranean tuco-tuco Ctenomys talarum (Rodentia: Ctenomyidae): contrasting the demographic consequences of regional and habitat-specific histories

MORA, MATIAS S.; LESSA, ENRIQUE P.; CUTRERA, ANA P.; KITTLEIN, MARCELO J.; VASSALLO, ALDO I.

MOLECULAR ECOLOGY

Blackwell Scientific

Lugar: London; Año: 2007 vol. 16 p. 3453 - 3465

0962-1083

In this work we examined the phylogeography of the South American subterranean herbivorous rodent Ctenomys talarum (Talas tuco-tuco) using mitochondrial DNA Control Region (D-loop) sequences, and we assessed the geographic genetic structure of this species in comparison with that of subterranean Ctenomys australis, which is parapatric to C. talarum and also lives in a coastal sand dune habitat (Mora et al. 2006). A significant apportionment of the genetic variance among regional groups indicated that putative geographic barriers such as rivers substantially affected the pattern of genetic structure in C. talarum. Furthermore, genetic differentiation is consistent with a simple model of isolation by distance, possibly evidencing equilibrium between gene flow and local genetic drift. In contrast, C. australis showed limited hierarchical partitioning of genetic variation and departed from an isolation by distance pattern. Mismatch distributions and tests of neutrality suggest contrasting histories of these two species: C. talarum appears to be characterized by demographic stability and no significant departures from neutrality, whereas C. australis has undergone a recent demographic expansion and/or departures from strict neutrality in its mtDNA.