Homologous
Structures or genes that share a common evolutionary origin, even if they have different current functions. Evidence of descent from a common ancestor.
Used in the Books
This term appears in 3 chapters:
"Recombination**: Sexual reproduction shuffles existing genetic variants through meiotic recombination (crossover between homologous chromosomes). While not creating new mutations, recombination generates new combinations, increasing variation."
"...ay evolution? Trends in Biochemical Sciences, 28(6), 336-341. [^4]: McGinnis, W., Garber, R. L., Wirz, J., Kuroiwa, A., & Gehring, W. J. (1984). A homologous protein-coding sequence in Drosophila homeotic genes and its conservation in other metazoans. Cell, 37(2), 403-408. [^5]: Cohn, M."
"...e incorrect segment. Double-strand break repair: Fixes breaks in both DNA strands (the most dangerous type of damage). Two major pathways exist: homologous recombination (uses the intact sister chromosome as a template for accurate repair) and non-homologous end joining (directly ligates broken ends, fas..."
Biological Context
The human arm, whale flipper, and bat wing are homologous—all derived from the same ancestral limb structure. Homology is evidence for evolution. In genetics, homologous chromosomes are matching pairs inherited from each parent.