Monotremes reveal previously unknown diversity in the DMRT gene family central to sexual development

Researchers have posted a preprint on bioRxiv reporting a comparative genomic analysis of the DMRT gene family in monotremes — the egg-laying mammals comprising platypus and echidna — with the aim of resolving longstanding questions about DMRT gene evolution in vertebrates.

DMRT genes encode transcription factors defined by a highly conserved DNA-binding domain (the DM domain) and are central to sexual development across metazoans. The best-characterised member, DMRT1, functions as a sex regulator universally in metazoans; in birds it is located on the Z chromosome and acts as a dosage-dependent primary sex-determination factor. Monotremes are of particular evolutionary interest because they possess an unusual multi-chromosome sex-determination system that is only distantly related to the therian XY system of placental mammals.

The preprint describes novel DMRT gene duplications and losses in monotreme lineages and proposes revised interpretations of gene family evolution in early mammals. The findings are relevant to researchers in evolutionary genomics, sex-determination biology, and comparative genomics, and have potential applications as a teaching resource for undergraduate and postgraduate genetics. As a preprint, the findings await peer review.