Homology that arises via gene duplication.

Closely related genes that arose through a genetic duplication event. Through evolution, the end result is two sequence-related genes and cognate proteins that may or may not have redundant or complementary function. Bioinformatics techniques can identify paralogous proteins based on gene and protein sequences and are useful for helping identify unknown proteins. See also Conservation, Domain, Homology, Orthology.

Paralogous molecular sequences result from gene duplication (independent of organism speciation), exist in multiple copies per organism, and will reconstruct gene phylogeny rather than species phylogeny (which may not be congruent) (cf. orthology).

Similarity of structure despite difference of function; the opposite of analogy.

False reasoning; paralogism.