A comparison of heterochromatic regions in three species ofneotropical canids

Abstract

Repetitive DNA varies in nature and abundance, and has had an important role in genome evolution of higher eukaryotes. In the present study we analyzed the dynamics of heterochromatic regions and telomeric sequences in three endemic South American canid species, Chrysocyon brachyurus, Lycalopex gymnocercus, and two subspecies of Cerdocyon thous by means of C-banding and fluorescence in situ hybridization (FISH) with telomeric probes. The three species revealed different banding patterns evidencing amplifications of centromeric heterochromatic and telomeric regions co-localized with telomeric sequences in L. gymnocercus and C. thous, and the presence of a heterochromatic terminal block in the Y chromosome of C. brachyurus. Additionally, an unusual heteromorphism of chromosome pair 1 was observed in the subspecies Cerdocyon thous entrerrianus. Our work emphasizes the importance of cytogenetic studies at the population level comprising the largest possible area of the geographic distribution of the species.