Homolog is a term commonly used in genetics, referring to a gene or chromosome that has a similar structure and function as another gene or chromosome in the same species or in a related species. Synonyms for homolog include ortholog, paralog, and analog. Orthologs are genes that share common ancestry and typically have a similar function across different species. Paralogs arise from gene duplication events and may have diverged in function from their ancestral gene. Analogous genes or structures have a similar function but do not share a common origin. Understanding the relationships between homologs and their variants help researchers to better understand evolutionary processes and genetic inheritance.