Which of the following events, occurring within a tandem repeat sequence, will cause an expansion or contraction of the array?
A) Endoduplication B) homologous recombination C) Unequal crossing-over D) Error-prone DNA repair E) Inversion
I know for a fact that upon replication, tandem repeats of DNA (specifically trinucleotide repeats) can form loops which are repaired by mismatch repair enzymes (MSH2-MSH3); and failure to correct this would lead to an expansion of the array post-replication. However, this answer was incorrect.
Could someone assist me with this question? I read up on the topic but its not clear to me why DNA repair defects do not suffice as an answer. I don't also necessarily understand the correct answer (C)
Thanks so much