Sometimes, it is also possible that two sequences have derived from a common ancestor, but may have diverged to such an extent that the common ancestral relationships are not recognizable at the sequence level.

Pairwise Sequence Alignment (PSA) is used to identify regions of similarity that may indicate functional, structural and/or evolutionary relationships between two biological sequences (protein or nucleic acid).

Topics include: Sequence Homology Versus Sequence Similarity and Identity, Methods, & Statistical Significance of Sequence Alignment.

Related Test: Bioinformatics Practice Test Questions: Sequence Alignment