Temperature-sensitive mutant

A temperature-sensitive (ts) mutant is a type of mutant organism, typically a bacterium, yeast, or animal cell, that exhibits a normal phenotype at a permissive temperature but displays a different phenotype, often a phenotype related to loss of function, at a non-permissive temperature. This change in phenotype is usually due to alterations in protein structure or function caused by mutations in the genes coding for those proteins. Temperature-sensitive mutants are particularly useful in genetic research and developmental biology.