In human genetics, the Y-chromosomal most recent common ancestor (Y-MRCA, informally known as Y-chromosomal Adam) is the most recent common ancestor (MRCA) from whom all currently living people are descended patrilineally. The term Y-MRCA reflects the fact that the Y chromosomes of all currently living males are directly derived from the Y chromosome of this remote ancestor. The analogous concept of the matrilineal most recent common ancestor is known as "" (mt-MRCA, named for the matrilineal transmission of mtDNA), the most recent woman from whom all living humans are descended matrilineally. As with "Mitochondrial Eve", the title of "Y-chromosomal Adam" is not permanently fixed to a single individual, but can advance over the course of human history as paternal lineages become extinct.
Estimates of the time when Y-MRCA lived have also shifted as modern knowledge of human ancestry changes. In 2013, the discovery of a previously unknown Y-chromosomal haplogroup was announced, which resulted in a slight adjustment of the estimated age of the human Y-MRCA.
By definition, it is not necessary that the Y-MRCA and the mt-MRCA should have lived at the same time, While estimates as of 2014 suggested the possibility that the two individuals may well have been roughly contemporaneous (albeit with uncertainties ranging in the tens of thousands of years), the discovery of archaic Y-haplogroup has pushed back the estimated age of the Y-MRCA beyond the most likely age of the mt-MRCA. As of 2015, estimates of the age of the Y-MRCA range around 200,000 to 300,000 years ago, roughly consistent with the emergence of anatomically modern humans.
Y-chromosomal data taken from a neanderthal from El Sidrón, Spain produced a Y-T-MRCA of 588,000 years ago for neanderthal and Homo sapiens patrilineages, dubbed ante Adam and 275,000 years ago for Y-MRCA.
The Y-chromosomal most recent common ancestor is the most recent common ancestor of the Y-chromosomes found in currently living human males.