Question

Which of the following is incorrect regarding sequence homology?

(a) Two sequences can homologous relationship even if have do not have common origin

(b) It is an important concept in sequence analysis

(c) When two sequences are descended from a common evolutionary origin, they are said to have a homologous relationship

(d) When two sequences are descended from a common evolutionary origin, they are said to share homology

I have been asked this question in exam.

My question comes from Sequence Homology Versus Sequence Similarity and Identity topic in section Pairwise Sequence Alignment of Bioinformatics

Answer 1

Right choice is (a) Two sequences can homologous relationship even if have do not have common origin

For explanation I would say: Homologous relationships are more certain when the sequences have common evolutionary origin. A related but different term is sequence similarity, which is the percentage of aligned residues that are similar in physiochemical properties such as size, charge, and hydrophobicity.