Testing of a canalization model of adaptive chromosomal evolution on a new theriological material

Abstract

Aims. The attempt to test a canalization model of adaptive chromosomal evolution which implies that for each adaptive zone there is an optimum karyotype by that can be evolved chromosomal rearrangements has been made on a new theriological material. Materials and methods. The intraspecies chromosomal variability in some African (Desmomys harringtoni) and Palaearctic (Terricola subterraneus, Sicista subtilis and S. betulina) species of rodents has been analyzed, using G-, C-banding. Results. The altitudional and (or) geographical gradients in intraspecies chromosomal variability which agree with gradients in physical and geographical conditions have been marked for models under consideration. Conclusions. Clinal nature of chromosomal variability in objects under study can be considered as a support for a canalization model of chromosomal evolution, but also can be the result of introgressive hybridization of two previously isolated populations that have acquired in the past in isolation monomorphism on different variants of character, now mixed in a wide range in the absence of significant physical and geographical barriers.

Key words: rodents, species, chromosomal variability, clinal nature, canalization model.