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Nucleotide substitutions occur by mistake in a segment of ribosomal RNA at a constant rate of one substitution every 10,000 years. A biologist has compared the ribosomal RNA of two modern0day species and found that they have six differences in their sequences. How many years ago did these species diverge from a common ancestor? (2 points)

Select one:

A3,000 years ago
B60,000 years ago
C30,000 years ago
D6,000 years ago

Verified Answer :

MiniZombie

Each on diverged from the common ancestor and has its own accumulated mutations. If they have six differences each it would be 10,000 years per one mistake giving you a total of 60,000 years ago.

Answer:

Option B, 60,000 years ago

Explanation:

It is given that the rate of substitution is one substitution per \(10,000\)years

Thus, starting from the base year

Number of substitution after \(10,000\)years \(= 1\)

Number of substitution after \(20,000\)years \(= 2\)

Number of substitution after \(30,000\)years \(= 3\)

Number of substitution after \(40,000\)years \(= 4\)

Number of substitution after \(50,000\)years \(= 5\)

Number of substitution after \(60,000\)years \(= 6\)

Thus, it is clear that \(6\) substitution or changes will occur in \(60,000\)years.

Thus, option B is correct.

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