Answer:
Frequency of the allele "r"causing the disease on Tristan da Cunha %
Frequency of the allele "r"causing the disease in the original population of 15 colonists %
Explanation:
Frequency of the allele "r"causing the disease on Tristan da Cunha
Given -
Out of 240 descendants on the island, 4 had retinitis pigmentosa (rr).
As per Hardy Weinberg's equllibrium equation
The frequecy of recessive individual in a given population is represented by
And q represents the frequency of allele r
So, in this case q is equal to
%
Frequency of the allele "r"causing the disease in the original population of 15 colonists
As it is given in the question statement , the frequency of allele "r"causing the disease in the original population of 15 colonists is ten times the frequency of the allele "r"causing the disease on Tristan da Cunha
i.e
%