W

Wave of advance: A favorable allele advances behind a moving cline, known as a wave of advance.
Wild type: The commonest allele at a locus or the most common phenotype.
Wobble pairing: The ability of tRNA to hybridize with codons even when only the first two nucleotides follow the standard G‑C and A-U base-pairing rules.
Weight: A system of units for expressing heaviness or mass, the amount or quantity of heaviness or mass.