Haven't had a lot of time for updates to the blog lately. However, I have a few beetle related publications recently.
1) An article that contains a lot of my dissertation research came out this summer in Genetics. In this paper I use the karyotypes, specifically sex chromosome morphology, from over 1,000 beetles to make inferences about the mode and tempo of sex-limited chromosome turnover across Coleoptera. The results of this study inspired the "fragile Y hypothesis". This hypothesis predicts that the characteristics of meiosis in a clade have a large impact on the rate of Y chromosome turnover and that sexually antagonistic selection reduces the size of the PAR (this is the region of the sex chromosome that forms chiasmata and recombines insuring proper segregation) to such an extent that faithful segregation becomes difficult. Beetles are an interesting group to test these ideas in because some clades have X and Y chromosomes that do not have a PAR and don’t come together and form chiasmata instead the are held together at a distance by proteins. While many other species have a more traditional meiosis where a PAR allows for chiasmata insuring proper segregation. When we compare the rate of Y chromosome turnover in these two groups we find that those with distance pairing sex chromosome are less likely to lose their Y chromosome. When we look to mammals we see a replication of this pattern suggesting that this is an important aspect of sex chromosome evolution in many clades with heterogametic sex determination.
Blackmon,H., & Demuth, J. P. (2014). Estimating tempo and mode of Y chromosometurnover: explaining Y chromosome loss with the fragile Y hypothesis. Genetics,197(2), 561-572.
2)I spent last fall semester at the National Evolutionary Synthesis Center in Durham North Carolina. During my time there I was working as part of the Tree of Sex Working Group to collect and curate karyotypes and sexual system data for all arthropods. This work led to over 11,000 records for arthropods which are now part of a database that is approaching 30K records in all across the tree of life. I also had the chance to make some really cool figures for this paper to help illustrate the distribution of data in our database.
Ashman,T. L., Bachtrog, D., Blackmon, H., Goldberg, E. E., Hahn, M. W., Kirkpatrick,M., ... & Vamosi, J. C. (2014). Tree of Sex: A database of sexual systems. ScientificData, 1.
3) Finally I also had the opportunity to write an article for the Ontario Entomological Society doing a review of sex chromosome and chromosome number evolution across Coleoptera. This was an enjoyable article to write. I was able to talk a bit about some of the early pioneers that used beetles to discover important aspects of basic biology in the early 1900s.
Blackmon, H. (2014) Coleoptera Karyotypes: The evolution of sex chromosomes and chromosome number. ESO Newsletter 19(1), 18-21.