Chapter 26.3, Problem 1CS

Core Skill: Modeling The goal of this modeling challenge is to revise the model shown in Figure 26.22 to account for recent data indicating that some modern Africans have a small amount of Neanderthal DNA.

Modeling Challenge: As discussed in this section, between 1% and 4% of the DNA of modern humans of European descent is derived from that of Neanderthals. Though most modern humans of African descent do not carry Neanderthal DNA, recent evidence has shown that some of them carry a very small amount. Assuming that the presence of this Neanderthal DNA is not due to recent interbreeding between modern humans of European and African descent, revise the model shown in Figure 26.22 to account for the observation.

Figure 26.22 A simplified model for the origin and spread of Homo sapiens throughout the world. This map, based on differences of mtDNA throughout current members of the world’s population, suggests Homo sapiens originated in East Africa. About 100,000 years ago, the species spread into the Middle East and from there to Europe, Asia, Australia, and the Americas.