The human and chimpanzee sequences for a particular DNA segment are being aligned.Both happen to be the same length, but you know that there is a three-nucleotide insertion in the chimpanzee sequence, relative to the human sequence.The most likely explanation is that there was a

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Quizplus · Accepted Answer

A three-nucleotide insertion in the chimpanzee sequence would cause a misalignment with the human sequence. One way to restore the alignment is by assuming a deletion in the chimpanzee sequence that matches a gap in the human sequence. Alternatively, one could assume an insertion in the human sequence, but this would be less parsimonious as it would require postulating a mutation that did not occur in the chimpanzee lineage. The other choices (B, C, D, E) do not account for the observed difference in length between the sequences.

The Human and Chimpanzee Sequences for a Particular DNA Segment