The use of phenotype or protein information to identify the gene encoding the protein.
The experimental procedure that begins with a cloned segment of DNA, or a protein sequence, and uses this knowledge to introduce programmed mutations (through directed mutagenesis) back into the genome in order to investigate gene and protein function.
An experimental approach that begins with information about the primary DNA or protein sequence and uses this knowledge to generate targeted mutations (heritable changes) or altered expression levels. Observation of the resulting effects on the organism (a physical attribute such as the color of the flower or the shape of the leaf) yields information about the physiological function of the gene or protein. This is the reverse strategy to a classical genetics approach that proceeds from observing a defined genetic trait towards obtaining sequence information for a specific gene.