Characteristic of an organism, tissue, etc. that is losing or has lost viability; lacking full physiological or metabolic function; not living.
Of a mutation, mutant gene, etc.: associated with reduced viability but allowing a significant proportion (typically more than 10 per cent) of affected individuals to survive or reach maturity. Also: of, relating to, or carrying such a mutation, gene, etc. Compare "semi-lethal", "sublethal".
A subvital mutation, mutant gene, etc.
Mid 19th century; earliest use found in Chambers's Edinburgh Journal. From sub- + vital.