Population cytogenetics of the "Northern Mod 1" chromosomal race of Liolaemus monticola Müller & Helmich (Iguanidae) from Central Chile

Abstract

We report the "Northern 2n=38-40, modifi cation 1" race from three localities of the Liolaemus monticola complex in Chile that appears to be chromosomally and geographical intermediate between two previously described "Northern 2n=38-40" and "Multiple Fission, 2n=40-44 (MF)" races. This race retains the same "Northern" chromosomal features, but differs by being both polymorphic for an enlarged chromosome pair 6 and for a pericentric inversion in chromosome pair 7; these rearrangements are present in the "MF" race. At the population cytogenetics level, the mean proportion of polymorphic chromosomes in the "Northern, mod 1" race is relatively high and intermediate between the Northern" and "MF" races, while the chromosome "alleles" in the "Northern, mod 1" race deviate from the Hardy-Weinberg ratio higher than the aforementioned races. The Roger's distance between samples are in concordance with the chromosome races and the proposals barriers (The Colorado river and the Juncal river). The lowest chromosome "alleles" flux values (Nm) are between the chromosomal races, suggesting a low chromosomal introgression. These population cytogenetics patterns, plus the origin of the chromosomal rearrangements, and the recombination patterns resulting from chromosomal heterozygosity are compared with the situation of other populations of the "Northern" and the "MF" races previously described. We discuss the possible "Northern, mod 1" hybrid status in the evolution of this complex in central Chile.