|
The degree to which a gene is expressed in the phenotype. Most dominant alleles show complete penetrance. However a gene may be affected by environmental factors to the extent that not all the individuals with a particular genotype show the phenotype characteristic of that genotype. In some maize plants, for example, anthocyanin pigment only develops in those parts of the plant exposed to high light intensities. In shaded parts of the plant the gene is not expressed. A gene whose expression is affected in this way is said to show incomplete penetrance.
|
