What do we know about the heterochromatin of capuchin monkeys (Cebus: Platyrrhini)?

Abstract

Cytogenetic studies in Cebus spp. have highlighted a peculiar genomic feature: the presence of conspicuous regions of extracentromeric heterochromatin distributed throughout the karyotype. This study investigates the distribution, variability and composition of heterochromatin and their possible implications for genome dynamics. We performed a molecular cytogenetic analysis in 253 individuals from seven of the 12 currently recognized species. The proportion of heterochromatin was related to genome size and ranked, from smallest to largest, from C. xanthosternos to C. albifrons. Interspecies comparative genome hybridization analyses suggested that the differences among species are not related to heterochromatin content but to changes in the Y chromosome. The pattern revealed by DAPI/CMA3 staining showed that Cebus heterochromatic DNA has a GC-rich composition. The distribution frequencies of heteromorphisms and polymorphisms were not randomly distributed, because a distinguishable pattern could be recognized for each group. Cebus cay and C. nigritus had a higher level of heterochromatin variability than previously reported. In conclusion, the wide variability among species of the genus Cebus is mostly due to the repetitive DNA fraction of its genome.