Scientists Reshape Y Chromosome Haplogroup Tree Gaining New Insights Into Human Ancestry ScienceDaily (Apr. 3, 2008) — The Y chromosome retains a remarkable record of human ancestry, since it is passed directly from father to son. In an article published in Genome Research scientists have utilized recently described genetic variations on the part of the Y chromosome that does not undergo recombination to significantly update and refine the Y chromosome haplogroup tree. Human cells contain 23 pairs of chromosomes: 22 pairs of autosomes, and one pair of sex chromosomes. Females carry a pair of X chromosomes that can swap, or...