This web page was produced as an assignment for Genetics 564, an undergraduate capstone course at UW-Madison.
Homology is broadly defined as a shared ancestry between a pair of structures, genes, or proteins, between different species . A classic illustration of the principle of homology is the bone structure of the forelimbs of vertebrates (Fig.1). Even though the function of these structures may diverge over time (Human vs. Bird) they still share a common origin. The same definition of homology can be applied to genes and proteins, that is homologous genes or proteins are those that share a common ancestor. There are two types of homologs, orthologs and paralogs. Orthologs are homologous genes resulting from a speciation event . Paralogs are homologous genes resulting from a gene duplication event .