Evolution

DNA and Most Recent Common Ancestor (MRCA)

We know there is a population bottleneck at about 8,000 BC, right after the Younger Dryas era. This is the start of the Neolithic Revolution. It is possible for this bottleneck to coincide with the existence of our MRCA. From Wikipedia:

Depending on the survival of isolated lineages without admixture from Modern migrations and taking into account long-isolated peoples, such as historical tribes in central Africa, Australia and remote islands in the South Pacific, the human MRCA was generally assumed to have lived in the Paleolithic period.

However, Rohde, Olson, and Chang (2004)[2], using a non-genetic model, estimated that the MRCA of all living humans may have lived within historical times (3rd millennium BC to 1st millennium AD). Rohde (2005)[4] refined the simulation with parameters from estimated historical human migrations and of population densities. For conservative parameters, he pushes back the date for the MRCA to the 6th millennium BC (p. 20), but still concludes with a "surprisingly recent" estimate of a MRCA living in the second or first millennium BC (p. 27). An explanation of this result is that, while humanity's MRCA was indeed a Paleolithic individual up to early modern times, the European explorers of the 16th and 17th centuries would have fathered enough offspring so that some "mainland" ancestry by today pervades even remote habitats. The possibility remains, however, that a single isolated population with no recent "mainland" admixture persists somewhere, which would immediately push back the date of humanity's MRCA by many millennia. While simulations help estimate probabilities, the question can be resolved authoritatively only by genetically testing every living human individual.

Other models reported in Rohde, Olson, and Chang (2004)[2] suggest that the MRCA of Western Europeans lived as recently as AD 1000. 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 estimates for this are similarly uncertain, but date to considerably earlier than the MRCA, according to Rohde (2005) roughly to between 15,000 and 5,000 years ago.[4] [1].

1. ^ a b c Dawkins, Richard (2004). The Ancestor's Tale, A Pilgrimage to the Dawn of Life. Boston: Houghton Mifflin Company. ISBN 0-618-00583-8.
2. ^ a b c Rohde DLT, Olson S, Chang JT (2004) "Modelling the recent common ancestry of all living humans". Nature 431: 562-566.
3. ^ Notions such as Mitochondrial Eve and Y-chromosomal Adam yield common ancestors that are more ancient than for all living humans (Hartwell 2004:539).
4. ^ a b Rohde, DLT , On the common ancestors of all living humans. Submitted to American Journal of Physical Anthropology. (2005)

So, three things happen at once: The Younger Dryas event; a population bottleneck; and the Neolithic Revolution. Thus, the theory that a common ancestor of mankind (Adam and Eve) lived in the near East (The Fertile Crescent, The Levant, or Upper Mesopotamia) is as good a theory as any other, and is supported by the Genesis story, as well as other creation myths.