Question

PLEASE HELP!

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.
Be sure to answer this question in paragraph form using complete sentences.

Answer 1

The answer to your question is below

Step-by-step explanation:

- The first thing we have to do is to look for the number of bases that are different between the two sequences of DNA.

Species A: GTACCTAAGTTCACCGAATT

Species B: GAACCTAAGGGCACCGAACT

There are three changes of bases between the two species that means 3 mutations.

If one mutation means 20 million years three mutations will mean

1 mutation -------------- 20 millions years

3 mutations ----------- x

x = (3 x 20 000 000) / 1

x = 60 000 000

That means that the species share a common ancestor 60 million years ago.