Research in my lab focuses on the regulation of the mammalian X chromosome. Males have one X and a Y chromosome while females have two X chromosomes. This has resulted in the evolution of mechanisms of dosage compensation. Mechanisms of dosage compensation are based on epigenetic modifications that take place during embryonic development and are tied to stem cell factors. We have found chromatin modifications associated with increased expression from the male X chromosome and are investigating the timing of these events during stem cell differentiation and embryo development (in collaboration with C. Ware). We have also developed unique resources to follow allele-specific expression of genes in a global fashion and to investigate the chromatin organization of the mouse genome (in collaboration with T. Blau) during development and in embryonic stem cells.