In human population genetics, Y-Chromosome haplogroups define the major lineages of direct paternal (male) lines back to a shared common ancestor in Africa.
Y-Chromosome Haplogroups all form "family trees" or "phylogenies", with both branches or sub-clades diverging from a common haplogroup ancestor, and also with all haplogroups themselves linked into one family tree which traces back ultimately to the most recent shared male line ancestor of all men alive today, called in popular science Y Chromosome Adam.
With this work, they strengthened their recommendation to move to a nomenclature system they referred to as shorthand (Karafet 2008).
They created a web based tree that attempted to be timely and had annual benchmark versions.
[citation needed] The table below brings together all of these works at the point of the landmark 2002 YCC Tree.