To determine whether interbreeding took place among Homo species before the populations that became modern humans left Africa, evolutionary biologists studied DNA from two African hunter-gatherer groups, the Biaka Pygmies and the San, and from a West African agricultural population, the Mandenka. Each of these groups is descended from populations thought to have remained in Africa, meaning they would have avoided the genetic bottleneck effect that usually occurs with migration. This means the groups show particularly high genetic diversity, which makes their genomes more likely to have retained evidence of ancient genetic mixing. The researchers looked at 61 non-coding DNA regions in all three groups. Because direct comparison to archaic specimens wasn't possible, the authors used computer models to simulate how infiltration from different populations might have affected patterns of variation within modern genomes. On chromosomes 4, 13 and 18 of the three African populations, the researchers found genetic regions that were more divergent on average than known modern sequences at the same locations, hinting at a different origin.
Question: Since the genetic diversity of the three African populations was high, while that of the indigenous population was low, researchers concluded that the three African populations had interbred.
Options:
A. true, B. false, C. uncertain
Answer: B