a molecule that can be used as a molecular clock has a neutral rate of one mutation per 12 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 six mutations?
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SEE ANSWER
If the neutral rate of mutation for the molecule is one mutation per 12 million years, and the two species differ by a total of six mutations, then we can calculate the time since their common ancestor by multiplying the number of mutations by the rate:
6 mutations * 12 million years/mutation = 72 million years
Therefore, the two species shared a common ancestor approximately 72 million years ago.
To determine the number of years ago two species shared a common ancestor, we need to calculate the time it takes for the observed number of mutations to occur.
Given that the neutral mutation rate is one mutation per 12 million years and the two species differ by a total of six mutations, we can use the mutation rate to calculate the time.
The total number of mutations (six) divided by the mutation rate (one per 12 million years) gives us the number of time intervals that have occurred.
6 mutations / 1 mutation per 12 million years = 6 time intervals
To calculate the number of years, we multiply the number of time intervals by the length of each interval.
6 time intervals * 12 million years per interval = 72 million years
Therefore, two species shared a common ancestor approximately 72 million years ago.