Genetic Modeling of Human History Part 1: Comparison of Common Descent and Unique Origin Approaches

Abstract

In a series of two papers (Part 1 and 2) we explore what can be said about human history from the DNA variation we observe among us today. Population genetics has been used to infer that we share a common ancestry with apes, that most of our human ancestors emigrated from Africa 50 000 years ago, that they possibly had some mixing with Neanderthals, Denisovans and other archaic populations, and that the early Homo population was never smaller than a few thousand individuals. Population genetics uses mathematical principles for how the genetic composition of a population develops over time through various forces of change, such as mutation, natural selection, genetic drift, recombinations and migration. In this article (Part 1) we investigate the assumptions about this theory and conclude that it is full of gaps and weaknesses. We argue that a unique origin model where humanity arose from one single couple with created diversity seems to explain data at least as well, if not better. We finally propose an alternative simulation approach that could be used in order to val- idate such a model. The mathematical principles of this model are described in more detail in our second paper (Part 2).