SICB Division of Ecology and Evolution (DEE)

DEE Researchers Database Entry

Daniel Janes

The origins of heteromorphic sex chromosomes
The current constitution and future degeneration of sex chromosomes have been discussed widely in scientific literature but the evolutionary history of sex chromosomes has not received commensurate attention. As a postdoctoral fellow in the Museum of Comparative Zoology, I am collecting data to address long-standing hypotheses on the origins of heteromorphic sex chromosomes. Sex chromosomes, as exemplified in birds and mammals, are believed to have arisen from two pairs of ancestral reptilian autosomes. Doctor Scott Edwards and I will screen bacterial artifical chromosome (BAC) libraries and genome databases to characterize sequences that are sex-linked, sex-specific, and sex-determining in birds and mammals and compare their structure to potential homologs in reptiles. Initially, we will characterize transitions from ancestral autosomes in alligators to derived heteromorphic sex chromosomes in emus, other birds, and mammals. Our results will have broader relevance for research on sex-determining mechanisms, the evolution of sex, and causes of sympatric speciation.