Understanding Mutation Fixation Probability
The probability of a new neutral mutation becoming fixed in a population depends on the population size. A neutral mutation is one that does not confer any survival or reproductive advantage or disadvantage.
Calculating Fixation Probability
For a diploid organism, the probability of a single new neutral mutation reaching fixation is given by the formula:
$ P_{fixation} = \frac{1}{2N} $
Where:
- $P_{fixation}$ is the probability of fixation.
- $N$ is the number of diploid individuals in the population.
Applying the Formula
In this question:
- The population size ($N$) = 100 individuals.
- The mutation is neutral.
Substitute the value of $N$ into the formula:
$ P_{fixation} = \frac{1}{2 \times 100} $
$ P_{fixation} = \frac{1}{200} $
$ P_{fixation} = 0.005 $
Conclusion
The probability of fixation for the new neutral mutation is 0.005. This value is often rounded to three decimal places as requested.
Important Questions from Genetic drift
- In a diploid population of N individuals, the probability of fixation of a new neutral mutation (assuming no other mutation occurs) is _________.
- Two isolated populations M and N have population sizes of 100 and 1000 individuals, respectively. The starting allele frequencies p and q are 0.5 in both populations. Assuming no selection, which one of the following is expected after 100 generations?
- A few years ago, a very small population of zebrafish became isolated by a newly built dam. As a result, which statement is most likely to be true about this population of zebrafish now?
- Which two of the following processes can result in a decline in heterozygosity in populations?
I) inbreeding; II) genetic drift; III) mutation; IV) random mating - Which of the following processes typically does NOT contribute to increase in genetic variation?
