Data from: Conserved ZZ/ZW sex chromosomes in Caribbean croaking geckos (Aristelliger : Sphaerodactylidae)

Current understanding of sex chromosome evolution is largely dependent on
species with highly degenerated, heteromorphic sex chromosomes, but by
studying species with recently evolved or morphologically indistinct sex
chromosomes we can greatly increase our understanding of sex chromosome
origins, degeneration, and turnover. Here, we examine sex chromosome
evolution and stability in the gecko genus Aristelliger. We used RADseq to
identify sex-specific markers and show that four Aristelliger species,
spanning the phylogenetic breadth of the genus, share a conserved ZZ/ZW
system syntenic with avian chromosome two. These conserved sex chromosomes
contrast with many other gecko sex chromosome systems by showing a degree
of stability among a group known for its dynamic sex determining
mechanisms. Cytogenetic data from A. expectatus revealed homomorphic sex
chromosomes with an accumulation of repetitive elements on the W
chromosome. Taken together, the large number of female-specific A.
praesignis RAD markers and the accumulation of repetitive DNA on the A.
expectatus W karyotype suggests that the Z and W chromosomes are highly
differentiated despite their overall morphological similarity. We discuss
this paradoxical situation and suggest that it may, in fact, be common in
many animal species.