Chapter 11, Problem 8P

Humans and gorillas last shared a common ancestor about 10 million years ago. Humans and chimps last shared a common ancestor about 6 million years ago. The table that follows shows the corresponding genomic region from two gorilla gametes, three chimpanzee gametes, and three human gametes.

a.	Draw a cladogram similar to that in Fig. 11.6b to show the evolutionary relationships among these three species.
b.	The data reveal six polymorphisms among these eight genomes, at positions 2 (A or G), 3 (A or T), 4 (G or T), 7 (C or T), 8 (C or T), and 9 (G or T). On your cladogram, indicate approximately when the mutations that produced each of these polymorphisms occurred. For each allele, state whether it is ancestral, derived, or that you can’t tell.
c.	Infer the sequences in (i) the last common ancestor of humans and chimpanzees, and (ii) the last common ancestor of all three species. Use a question mark (?) to represent any uncertainty.