Humans and chimpanzees diverged about 6 million years ago.If 12 nucleotide substitutions have occurred between human and chimpanzee lineages in a sequence of mitochondrial DNA,and 36 have occurred between humans and gibbons,humans and gibbons,according to the molecular clock hypothesis,separated _______ million years ago.
A) 2
B) 6
C) 12
D) 18
E) 36

Question

Quizplus · Accepted Answer

According to the molecular clock hypothesis, the number of substitutions is proportional to the time since divergence. If 12 substitutions correspond to 6 million years, then 36 substitutions would correspond to 18 million years.

Humans and Chimpanzees Diverged About 6 Million Years Ago