The amino acids in the original partial sequence (N-term-...P-I-E...-C-term) have little to no impact on protein structure and function. However the amino acid sequence near the C-terminal end of the protein is required for normal function. Any amino acid changes in this region of the protein will result in a nonfunctional protein. Given this information, which reversion mutation in the gene would restore the normal function of the protein

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?