Question

Comparable segments of the mitochondrial DNA sequences of two similar species are shown below. This segment of DNA mutates at a rate of one base pair per 33 million years. Based on these DNA sequences, how long ago did the two species diverge from a common ancestor?

Species A mtDNA sequence: TACAAGATAC
Species B mtDNA sequence: TACGCGTAAC
99 million years ago
33 million years ago
66 million years ago
132 million years ago

Answer 1

99million years ago, so the answer is C

Answer 2

132 million years ago

Step-by-step explanation:

The two DNA mit have a difference of 4 bases. If the frequency of mutation is one every 33 million years. We can stipulate that the time that has passed since the two species diverged from a common ancestor is 132 million years. This can be calculated by multiplying the number of variations by the frequency.

4 (variations) x 33 million years = 132 million years.

Species A mt DNA : TACAAGATAC

Species B mtDNA: TACGCGTAAC