Question

Shorter sequences require higher cutoffs for inferring homologous relationships than longer sequences.

(a) True

(b) False

This question was addressed to me in an international level competition.

Query is from Sequence Homology Versus Sequence Similarity and Identity in section Pairwise Sequence Alignment of Bioinformatics

Answer 1

The correct option is (a) True

For explanation: For determining a homology relationship of two protein sequences, for example, if both sequences are aligned at full length, which is 100 residues long, an identity of 30% or higher can be safely regarded as having close homology. If their identity level falls between 20% and 30%, determination of homologous relationships in this range becomes less certain.