A gene exists in two alleles, which we will call B and b. The gene is 1123 bp in length, and the B and b alleles exhibit single base pair differences at six different sites. If gene conversion changed the b allele into the B allele, which mechanism would you favor to explain the conversion

The below options will complete the question

Select one:

a. Gap repair synthesis

b. Mismatch repair

c. Direct repair

d. Nucleotide excision repair

Our answer is surely A.

a. Gap repair synthesis

Explanation:

Alleles of gene B differ by 6 bps and are seeming close to each other among the 1123 bp within the particular gene, favouring the gap repair synthesis.

In the gap repair synthesis, a double stranded break is formed at a homologous chromosome with a small part of the gene or the 6 bps of the recessive allele

being digested away.

Strand invasion and a D-loop formation is followed by the new region being occupied by the dominant B allele to yielding dominant B allele in both chromosomes.

The gap repair synthesis allows the 6bps to be converted to the dominant B from the recessive b when in proximity/being close together.