Chapter 21, Problem 21P

Small population size causes genetic drift because of chance sampling of different alleles from one generation to the next. We can predict how much genetic drift occurs for a given population size using binomial sampling statistics. With a population of size N, we can estimate that 95% of the time the allele frequency (p) in the next generation will be within the confidence interval of $p\pm 1.96\left(\sqrt{\frac{p\left(1-p\right)}{2N}}\right)$, where $\frac{p\left(1-p\right)}{2N}$ is an estimate of the statistical variance in allele frequencies from one generation to the next with random sampling of 2N alleles each generation.

a.	What is the confidence interval for p = 0.5 when N = 100,000?
b.	What is the confidence interval for p = 0.5 when N = 10?
c.	How are the results in parts (a) and (b) related to the consequences of a population bottleneck?