Physical map of repetitive DNA and karyotype evolution in three species of the genus Omophoita (Coleoptera: Alticinae)

Abstract

The order Coleoptera comprises species that are used as models in evolutionary studies, such as Alticinae, which features giant sex chromosomes. Thus, the aim of the present study was to investigate the differentiation and evolution of the sex chromosome in species of the Omophoita genus (Alticinae) using repetitive DNA (total C0t-1), C-banding and base-specific fluorochromes. Analyses using probes generated through C0t-1 reassociation kinetics showed markers distributed across all the chromosomes, especially the sex chromosomes. In conclusion, repetitive sequences are distributed across the sex chromosomes and autosomes, demonstrating that the heterochromatin of the species is largely composed of repetitive DNA. Cross-hybridisation among the species produced a very similar staining pattern for the probes. Thus, we conclude that the majority of the genome of the species of Omophoita is shared, showing the heterochromatin to be largely composed of repetitive DNA distributed along the sex chromosomes and autosomes.