Homologous Recombination Occurs in a Heterozygote in Which Alleles D

question 53

Multiple Choice

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.