Question

Given current HIV infection rates in different geographic regions and the frequency of CCR5 alleles in different populations, which is the most likely change in the resistant CCR5 allele frequency we will observe in future generations?

a.An increase in CCR5 frequency in Europe

b.No change in CCR5 frequency in Europe or Africa

c.An increase in CCR5 frequency in Africa

d.An increase in CCR5 frequency in both Europe and Africa

Answer 1

Answer: Choice A

Explanation: Demographic studies have shown that the CCR5 allele frequency is very high in European population. This mutation allows them to prevent the entry of HIV into the host cells and thus prevents infection. This is why the population of this region has lowest incidences of HIV infection and hence these individuals survive better thus showing natural selection. Thus, this frequency is likely to increase due to enhancement in their fitness for survival.