Table 1.

Glossary of molecular evolution

Term	Definition
Homologous genes	Genes found in different species that have shared ancestry, includes both orthologous and paralogous genes.
Orthologous genes	Homologous genes in different species as a result of speciation.
Paralogous genes	Homologous genes that have duplicated within a genome.
Substitution	Mutation that has become fixed in a population, i.e. replaced all other nucleotide variants at the same position.
Nonsynonymous substitution	Fixed mutation in protein-coding sequence that results in amino acid change.
Synonymous substitution	Fixed mutation in protein-coding sequence that does not alter the amino acid.