9 letters · 14 points in Scrabble
noun an allele that produces its characteristic phenotype only when its paired allele is identical
adjective of or pertaining to a recession
adjective (of genes) producing its characteristic phenotype only when its allele is identical
originFrom Latin recēdō + -ive, or directly from New Latin recessīvus.
Etymology from Wiktionary, CC BY-SA 3.0