Isolate genomic clone, sequence it, and determine amino acid sequence. This sequence can be compared with that of the healthy organisms to deduce protein function in the organism, which is not equivalent in the mutant. Firstly, genetic approach begins at the gene level, comparing a normal gene to a mutant. It allows you to deduce amino acid sequence of the mutant protein and compare that with the sequence of the known protein to gain insight into the functioning of the protein. Temperature-sensitive mutants exhibit the wildtype phenotype under low temperatures, but exhibit the mutant phenotype at higher temperatures. Thus, conditions are permissive when the mutants are allowed to grow normally, or under lower temperatures: define (or compare and contrast): a) gene expression; transcription; replication; translation; b) gene; allele. Gene expression is the process by which the information from a gene is used in the synthesis of functional protein or rna product.