Question

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

...?

Answer 1

Answer:

40 million years would be the correct answer.

The molecular clock is a technique based on the mutation rate used to determine the time when two species diverged from a common ancestor.  

Mutation rate is defined as the rate at which a number of mutations taking place, that is, the number of mutations in unit time.

For example, the mutation rate in a provided question is one mutation per 5 million years, that is, one nucleotide is mutated in every 5 million years.

Thus, if the total of 8 mutations have taken place in the DNA sequence of two species that means a total of 8 x 5 = 40 million years would have been passed since they share a common ancestor.

Answer 2

"40 million years" ago did the two species share a common ancestor if the molecules found in these two species differ by a total of eight mutations. The correct option among all the options that are given in the question is the fourth option or the last option. I hope that this is the answer that has come to your help.