A certain segment of DNA can be used as a molecular clock. Its rate of mutation is one mutation per 20 million years. Examine the DNA segments from two different species:

Species A: GTACCTAAGTTCACCGAATT
Species B: GAACCTAAGGGCACCGAACT

Using this example, explain how this information can be used to determine how long ago these two species shared a common ancestor.

Question

A certain segment of DNA can be used as a molecular clock. Its rate of mutation is one mutation per 20 million years. Examine the DNA segments from two different species:
 
Species A: GTACCTAAGTTCACCGAATT
Species B: GAACCTAAGGGCACCGAACT
 
Using this example, explain how this information can be used to determine how long ago these two species shared a common ancestor.

anonymous · Answer

experiences base changes at a rate of .56 changes per base pair per billion years. If this rate is reliable, the gene could be used as a molecular clock. so the two species had a common ancestor about 80 million yr ago

anonymous · Answer

source: High School Honors Bio