title: Rare deep-rooting Y chromosome lineages in humans: lessons for phylogeography.
abstract: There has been considerable debate on the geographic origin of the human Y chromosome Alu polymorphism (YAP). Here we report a new, very rare deep-rooting haplogroup within the YAP clade, together with data on other deep-rooting YAP clades. The new haplogroup, found so far in only five Nigerians, is the least-derived YAP haplogroup according to currently known binary markers. However, because the interior branching order of the Y chromosome genealogical tree remains unknown, it is impossible to impute the origin of the YAP clade with certainty. We discuss the problems presented by rare deep-rooting lineages for Y chromosome phylogeography.
mesh_terms: D005075:Biological Evolution; D041322:Chromosomes, Human, Y / Q000235:genetics*; D006801:Humans; D008297:Male; D010163:Paleontology; D010802:Phylogeny