Cooperativity, specificity and evolutionary stability of Polycomb targeting in Drosophila

We report the evolutionary behaviour of Polycomb group proteins, their recruitment factors and their underlying sequences by performing ChIP-seq analysis in 4-5 different Drosophila species. We demonstrate an extremely high conservation of Polycomb repressive domains across Drosophila species We validate few cases of PRE divergence that shows that cis-driven PRE evolution is a rare event. We further show that PHO recruitment to Polycomb domains is evolutionarily robust to motif changes and that PRC1 stabilizes binding of its key recruiter Overall design: ChIP-seq analysis of histone marks and chromatin associated factors across 4-5 Drosophila species