On the Number of New World Founders: A Population Genetic Portrait of the Peopling of the Americas

I haven't tried (and am not sure if I could if I tried) to follow the mathematics (and the assumptions) in this modeling but I found the plain language results fascinating:

The estimated effective size of the founding population for the New World is fewer than 80 individuals...Analyses of Asian and New World data support a model of a recent founding of the New World by a population of quite small effective size.

Wolfgang