Final answer:
The correct answer is option C, A B C D E F G · H G I, which represents a reverse duplication with the segment 'G' duplicated and inserted in reverse order right after 'H'.
Step-by-step explanation:
A reverse duplication in genetics is when a segment of a chromosome is duplicated and then reinserted into the chromosome in reverse order. Given the normal gene sequence A B C D E F G · H I, we need to identify which option represents a reverse duplication, where a part of the gene sequence is duplicated and flipped.
Option C, A B C D E F G · H G I, shows that the segment 'G' just before the 'H' has been duplicated and inserted in reverse order, immediately following the 'H'. This results in the original 'G' being followed by another 'G' but in reverse order, which is consistent with the definition of a reverse duplication.