In 2010, a team of biologists led by Svante Paabo announced evidence

In 2010, a team of biologists led by Svante Paabo announced evidence that modern humans interbred with Neanderthals some 60,000–100,000 years ago. These researchers compared the full sequence of Neanderthal DNA to that of five modern humans from China, France, sub-Saharan Africa, and Papua New Guinea, and looked for DNA shared by both Neanderthals and non-African modern humans, but not by sub-Saharan Africans. Because Neanderthals and modern humans are known to have diverged hundreds of thousands of years before modern humans left Africa, Paabo attributed any such common DNA to interbreeding in Eurasia. Paabo’s team announced that the modern humans from China, France, and Papua New Guinea all have the same proportion of Neanderthal DNA, and inferred that interbreeding with Neanderthals must have taken place before the ancestor population of those Eurasians divided. Paabo maintained that these two events, the migration of modern humans out of Africa and the division of the Eurasian population, mark the interval during which the interbreeding must have taken place, and that for roughly forty thousand years of that window, Neanderthals and modern humans lived near one another in the Middle East.

The team’s conclusions were answered with skepticism on a number of fronts. Critics pointed out that an earlier report reached similar conclusions based on Neanderthal samples later found to be contaminated with DNA from modern humans. Paleontologists and archaeologists charged that the conclusion was unsupported by archaeological evidence. Further, Paabo’s team found evidence only of Neanderthal DNA in modern humans, not of modern human DNA in Neanderthals, but critics claim that interbreeding would result in gene flow in both directions.

1. The passage implies that which of the following claims is true?

I. Modern humans and Neanderthals share a common ancestor.
II. Modern humans and Neanderthals interbred.
III. Modern humans and Neanderthals lived near one another approximately 80,000 years ago.

A. I Only
B. III Only
C. I and III Only
D. II and III Only
E. I, II, and III


2. The passage suggests which of the following is true of Paabo’s critics?

I. they doubt Paabo’s integrity
II. they ignore DNA evidence
III. they sometimes appeal to archaeological evidence

A. I Only
B. II Only
C. III Only
D. I and II Only
E. II and III Only