Problem
Pingelapese islanders inhabit a small, isolated island in Micronesia. A typhoon reduced the population to around 20 individuals in the 18th century, which then recovered to its previous size of around 1000 individuals. The frequency of achromotopsia, an autosomal recessive condition causing total colour blindness, is now 1/24 among the islanders and 1/30,000 among neighbouring regions.
1. State the agent of change arising from the typhoon's impact on the Pingelapese population.
2. Explain whether selection is likely to remove achromotopsia from Pingelapese Islanders.
3. Calculate the frequency of achromotopsia among Pingelapese Islanders.
4. Calculate the frequencies of wild type (p) and achromotopsia (q) alleles?
5. Calculate the expected number of unaffected heterozygous individuals in a population of 1000. Show your working.