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
- Which one of the following statements about genetic drift is accurate?
- 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 In a population of birds on an island, the average beak size reduced over one generation. A researcher estimated the association between beak size and relative fitness, shown in the graph. The estimated slope was –0.05 with a 95% confidence interval of -0.15 to 0.09.
Which one of the following evolutionary processes acting on beak size is the most likely reason for the observed reduction in beak size?
- Two isolated populations X and Y have 100 and 10000 individuals, respectively. Both populations have the same starting allele frequencies of p=0.5 and q=0.5. After 1000 generations of genetic drift, which of the following statements is true about the heterozygosity at this locus in these two populations?
