Homologous recombination occurs in a heterozygote in which alleles D and d differ by a single base pair.The D allele has a G at one position, whereas the d allele has a C at the same position.If branch migration causes heteroduplex formation across this position, what is the expected outcome?
A)Both D and d alleles will remain unchanged because G can base pair with C.
B)Mismatch repair will identify an abnormal G-G base pair and may convert the D allele to a d allele.
C)Mismatch repair will identify an abnormal C-G base pair and will ensure that the cell has two copies of each allele.
D)Mismatches will cause the Holliday junction to be unstable and to resolve by the noncrossover pathway.

Question

Quizplus · Accepted Answer

Mismatch repair mechanisms can recognize mismatched base pairs (such as G-G) resulting from heteroduplex formation during homologous recombination. The repair process may then convert one allele to the other, in this case potentially converting the D allele (with a G) to the d allele (with a C) by replacing the incorrect G with a C.

Homologous Recombination Occurs in a Heterozygote in Which Alleles D