Figure 1

A phylogenetic tree of HP1 proteins. Species shown are Caenorhabditis elegans (Ce), Drosophila melanogaster (Dm), Drosophila virilis (Dv), Dictyostelium discoideum (Dd), Gallus gallus (Gg), Homo sapiens (Hs), Mus musculus (Mm), Neurospora crassa (Nc), Schizosaccharomyces pombe (Sp) and Xenopus laevis (Xl). Most animal species have several HP1 isoforms, but those in Drosophila and C. elegans are not generally orthologous with particular mammalian isoforms. The tree was adapted from the combined data from the Wellcome Trust Sanger Institute Pfam protein family database [76] and Simple Modular Architecture Research Tool (SMART) database [77].