Number of retrieved Ataxin-2 proteins in eukaryotes. The phylogenetic relationship between thirty-eight vertebrates, eighteen invertebrates, fifteen fungi, sixteen protists and forty viridiplantae genomes is displayed in a circle. Relationships were adapted from the National Center of Biotechnology Information (NCBI) taxonomy server (http://www.ncbi.nlm.nih.gov/Taxonomy) . The name of major group of organisms is displayed with a color code. The species abbreviations and the proteins are listed in Additional file 1.