A population of red bats has two alleles (A and A’) at the chymase gene. The relative fitness values of the three genotypes are wAA = 1.0, wAA’ = 1.0, and wA’A’ = 0.85. At time 0, the frequencies of the two alleles are f(A) = p = 0.15 and f(A’) = q = 0.85. What type of selection is operating at the chymase gene? Which allele (A, A’, or neither) is genetically dominant? Calculate s for this locus. Over time, will the frequency of allele A increase, decrease, or stay the same? Calculate the average fitness of this population. What will the frequency of the A allele be in generation 1?

Astudy by solloch and et. al., in 2017, gives the map above which shows the frequency of alleles with a ccr5-delta32 mutations over 87 different countries. this mutation deletes the presence of a co-receptor (ccr5) on the outside of human t-cells (lymphocytes). some viruses, such as the one responsible for the black death and human immunodeficiency virus (hiv), require this receptor for attachment to host cells during the infection process. the black death was an epidemic that passed over northern europe during the 14th century killing nearly 60% of europeans. according to this information, which explanation best explains why northern europeans show a greater immunity for hiv than some other parts of the world?