Homologs produced by speciation. Orthologs are g enes derived from a common ancestor that diverged due to divergence of the organisms they are associated with. They tend to have similar function.

Genes that code for proteins with a similar function, but exists in different species

Sequences from different species that perform the same biological function and are likely to be evolved from a common ancenstral sequence. See Paralogs.

Proteins from different organisms that evolved from a common protein ancestor to serve analogous functions in the respective organism. Deviations in sequence and structure between orthologs are expected to be smallest for amino acids important for function because the selective pressure against changing these residues is highest.

genes in different species that evolved from a common ancestral gene by speciation. They typically retain the same function in the course of evolution.