homolog

Meanings

1. 1
   noun

   a biological structure, organ, gene, or other feature that shares a common evolutionary origin with a corresponding feature

   A whale's flipper is a homolog of the human arm because both descend from the same ancestral forelimb.

2. 2
   noun

   genetics: one member of a pair of corresponding chromosomes, genes, or proteins related by common descent

   During meiosis, each chromosome aligns with its homolog before the pair separates.

3. 3
   noun

   chemistry: one compound in a homologous series whose members differ by a repeated structural unit

   Propane is the next homolog after ethane in the alkane series.

Borrowed through French homologue from Greek homologos, 'agreeing or corresponding,' formed from homos, 'same,' + logos, 'word, account, or relation.' Homolog is the usual American spelling; homologue remains common in British English.

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