Published online by Cambridge University Press: 01 January 2022
I propose a new account of homology, according to which homology is a correspondence of developmental mechanisms due to common ancestry, formally defined as an isomorphism of causal graphs over lineages. The semiformal definition highlights the role of homology as a higher-order principle unifying evolutionary models and also provides definite meanings to concepts like constraints, evolvability, and novelty. The novel interpretation of homology suggests a broad perspective that accommodates evolutionary developmental biology and traditional population genetics as distinct but complementary approaches to understand evolution, prompting further empirical and theoretical research.
I thank Yoshinari Yoshida, Günter Wagner, an anonymous reviewer, and audiences at PSA 2016 for helpful comments and questions and the editor of the journal for grammatical suggestions. Any remaining mistakes are my own. This work was supported by Japan Society for the Promotion of Science grant-in-aid 16K16335.