Phylogenetic tree of human Y chromosome, emphasizing the three star-like expansions (Oα, Oβ, Oγ).

<p>The tree was constructed from 78 samples sequenced in this study, together with three published East-Asian genomes and a chimpanzee genome. The branch lengths (horizontal lines) are proportional to the number of SNPs on the branch. Numbers in red indicate the coalescence time (in years, considering the variation in SNP counting, but ignoring uncertainty in mutation rate) and 95% confidence intervals of the node. For more details, see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0105691#pone.0105691.s002" target="_blank">Fig. S1</a>.