Question

If the two sequences share significant similarity, it is extremely ______ that the extensive similarity between the two sequences has been acquired randomly, meaning that the two sequences must have derived from a common evolutionary origin.

(a) unlikely

(b) possible

(c) likely

(d) relevant

Answer 1

Right answer is (a) unlikely

To explain I would say: Sequence alignment provides inference for the relatedness of two sequences under study. Regions that are aligned but not identical represent residue substitutions; regions which residues from one sequence correspond to nothing in the other represent insertions or deletions that have taken place on one of the sequences during evolution.