A molecule that can be used as a molecular clock has a neutral mutation rate of one mutation per 5 million years. How many years ago did two species share a common ancestor if the molecules found in these two species differ by a total of eight mutations? Answer 1.5 million years 10 million years 20 million years 40 million years
how would i solve this
40?
why a ?
The question is saying that a molecule starts out the same in two species that have just split. It says the molecule mutates (changes in some small way) once every 5 million years. So, after 5 million years, you expect to see one change in the molecule. After 10 million years, you expect to see 2 changes. So, how long do you have to wait to see 8 changes?
5-1 10-2 15-3 20-4 25-5 30-6 35-7 40-8
The answer is 20 million years. I took this test 3 times and every time the answer was 20 million years! :)
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