Y chromosome variants tip the epigenetic balance. Bernardo Lemos, Alan Branco, John Gibbons, Cristina Valente. Molecular & Integrative Physiological Sciences, Harvard School of Public Health, Boston, MA.

   The Drosophila Y chromosome is an unusual molecule. In D. melanogaster the chromosome is ~40 megabases, but harbors only ~14 protein coding genes. We have recently developed intra-specific and inter-specific Y chromosome introgression to uncover Y-linked regulatory variation: the quantitative effects that tracts of Y-linked chromatin exert on gene regulation. Here we combine several published datasets with ongoing experiments addressing allele specific expression analysis to provide new insights into the mechanisms by which Y chromosomes modulate genome-wide expression levels and epigenetic states. Our studies point to mechanisms that include both genetic and epigenetic components.