XX/XY Sex Chromosomes in the South American Dwarf Gecko (Gonatodes humeralis)

Abstract

Sex-specifc genetic markers identifed using restriction site-associated DNA sequencing, or RADseq, permits the recognition of a species' sex chromosome system in cases where standard cytogenetic methods fail. Thus, species with male-specifc RAD markers have an XX/XY sex chromosome system (male heterogamety) while species with female-specifc RAD markers have a ZZ/ZW sex chromosome (female heterogamety). Here, we use RADseq data from 5 male and 5 female South American dwarf geckos (Gonatodes humeralis) to identify an XX/XY sex chromosome system. This is the frst confdently known sex chromosome system in a Gonatodes species. We used a low-coverage de novo G. humeralis genome assembly to design PCR primers to validate the male-specifcity of a subset of the sex-specifc RADseq markers and describe how even modest genome assemblies can facilitate the design of sex-specifc PCR primers in species with diverse sex chromosome systems.