Identification of Z-linked genes for the study of sex chromosome evolution in Lepidoptera

Moths and butterflies (Lepidoptera) have a WZ/ZZ (female/male) sex chromosome system or its numerical variants. The non-recombining W chromosome is largely formed by heterochromatin, composed of repetitive DNA and almost free of genes. Its use for evolutionary studies is thus limited due to fast molecular divergence. Whereas the Z chromosome resembles to autosomes; it is rich in genes and thus expected to be more conserved. In this study, the Z-linked genes with available DNA sequence information are summarized in order to give reference to suitable candidates for the study on evolutionary history of sex chromosomes in Lepidoptera. The use of Zlinked genes to test current hypotheses on the origin of the lepidopteran W chromosome is also discussed