Human Y-chromosome DNA haplogroup

This article is about the human Y-DNA haplogroup. For the human mtDNA haplogroup, see Human mitochondrial DNA haplogroup.

In human genetics, a human Y-chromosome DNA haplogroup is a haplogroup defined by specific mutations in the non-recombining portions of DNA on the male-specific Y chromosome (Y-DNA). Individuals within a haplogroup share similar numbers of short tandem repeats (STRs) and single-nucleotide polymorphisms (SNPs). The Y-chromosome accumulates approximately two mutations per generation, and Y-DNA haplogroups represent significant branches of the Y-chromosome phylogenetic tree, each characterized by hundreds or even thousands of unique mutations.

The Y-chromosomal most recent common ancestor (Y-MRCA), often referred to as Y-chromosomal Adam, is the most recent common ancestor from whom all currently living humans are descended patrilineally. Y-chromosomal Adam is estimated to have lived around 236,000 years ago in Africa. By examining other population bottlenecks, most Eurasian men trace their descent from a man who lived in Africa approximately 69,000 years ago (Haplogroup CT). One study has suggested that Southeast Asia is the geographic origin for all non-African human Y chromosomes, however another study has disputed this due to the region being outside the possible range for admixture between Neanderthals and modern humans. Other bottlenecks occurred roughly 50,000 and 5,000 years ago, and the majority of Eurasian men are believed to be descended from four ancestors who lived 50,000 years ago, all of whom were descendants of an African lineage (Haplogroup E-M168).

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