A mutation that is manifest in only a limited temperature range. The product of such a gene generally functions normally, but is unstable above a certain temperature. Thus, the mutant when reared at the lower (permissive) temperature is normal, but when placed at the higher (restrictive) temperature shows the mutant phenotype. See Chronology, 1951, Horowitz and Leupold; 1971, Suzuki et al.; albinism, Himalayan mutant.
Subjects: Biological Sciences.