Using the molecular clock method for determining how long ago two species, A1 and A2, diverged, what would be the time estimate if species A1 differed from species A2 by 30 percent and the mutation rate were was 1 percent per million years?

Question

Quizplus · Accepted Answer

The molecular clock method assumes that mutations accumulate at a constant rate, so we can use the amount of genetic difference between two species and the mutation rate to estimate how long ago they diverged. If species A1 differed from species A2 by 30 percent, this means that there have been 30 mutations per 100 base pairs (or 0.3 mutations per base pair) since they last shared a common ancestor. If the mutation rate is 1 percent per million years, this means that there is 1 mutation per 100 base pairs (or 0.01 mutations per base pair) per million years. Therefore, we can estimate the time since divergence by dividing the genetic difference by the mutation rate:
0.3 / 0.01 = 30 million years.

Using the Molecular Clock Method for Determining How Long Ago