User:Peak/MRCA
MRCA
[edit]The MRCA of a set of individuals can sometimes be determined by referring to an established pedigree. In general, however, it is impossible to identify the specific MRCA of a set of individuals, but an estimate of the time at which the MRCA lived can often be given; such estimates can be given based on DNA test results and established mutation rates, or by reference to a non-genetic genealogical model.
MRCA of two individuals
[edit]The most recent common patrilineal ancestor of any two males, and the most recent common matrilineal ancestor of any two individuals can be determined by genealogical DNA tests. The tests use mitochondrial DNA for matrilineal inheritance or Y-chromosome-DNA for patrilineal inheritance.
MRCA of all living humans
[edit]The MRCA of everyone alive today may not have been the same individual as the MRCA of all humans alive at some other time. Also, the existence of an MRCA does not imply any sort of population bottleneck or first couple. The MRCA of everyone alive today co-existed with a large human population, most of whom either have no living descendants today or else are ancestors of almost everyone alive today.
Patrilineal and matrilineal ancestry
[edit]The most recent common patrilineal ancestor of all living male humans, and the most recent common matrilineal ancestor of all living female humans have been established by researchers using tests of the same kinds of DNA as for two individuals. Notions such as Mitochondrial Eve and Y-chromosomal Adam yield common ancestors that are more ancient than for all living humans. (Hartwell 2004:539) Mitochondrial Eve is estimated to have lived about 150,000 years ago. Y-chromosomal Adam is estimated to have lived between 60,000 and 90,000 years ago.
Time estimates
[edit]The MRCA of all living humans lived within historical times (3000 BC - 1000 AD), according to a non-genetic model reported in a 2004 article by Douglas Rohde, Steve Olson, and Joseph Chang, "Modelling the recent common ancestry of all living humans". Other models reported in the same article suggest that the MRCA of Western Europeans lived as recently as 1000 AD. The same article provides surprisingly recent estimates for the identical ancestors point, the most recent time when each person then living was either an ancestor of all the persons alive today or an ancestor of none of them. The actual MRCA is farther back if one attempts to take into account long-isolated peoples, such as historical tribes in central Africa, Australia and remote islands in the South Pacific.