penetrance /pen·e·trance/ (pen´ĭ-trins) the frequency with which a heritable trait is manifested by individuals carrying the principal gene or genes conditioning it.
penetrance
penetrance
pen·e·trance (p n  -tr ns)n. The frequency, under given environmental conditions, with which a specific genotype is expressed by those individuals that possess it, usually given as a percentage. |
penetrance
[pen′ətrəns]
Etymology: L, penetrare, to penetrate
the regularity with which an allele is expressed in a person who carries it. If an allele always produces its effect on the phenotype, it is fully penetrant. Achondroplasia is caused by a fully penetrant allele; if the allele is present, achondroplasia results. If an allele produces its effect less frequently than 100% of the time, it is not fully penetrant. Retinoblastoma develops in 90% of the children carrying the allele for the disease; in 10% of children the allele is nonpenetrant. penetrant, adj.
penetrance
the frequency with which a heritable trait is manifested by individuals carrying the principal gene or genes conditioning it.
incomplete penetrance
when penetrance is less than 100%.
penetrance
The frequency with which the characteristics transmitted by a gene appear in individuals possessing it. Penetrance is represented as the ratio of individuals who carry the gene and express its effects, over the total number of carriers of the gene in a population. Few of the genes in the genome show a high penetrance because environmental factors play a role in development. Examples: familial exudative vitreoretinopathy and neurofibromatosis (type 1 and type 2), which are both inherited as autosomal dominant, have 100% penetrance; about 90% of the children who carry the retinoblastoma gene develop the disease while the gene remains non-penetrant in the remaining 10% of the children. See expressivity; familial exudative vitreoretinopathy.
penetrance
Penetration The disruption of a surface, as in penetrating–eg, gunshot wounds, hospital-acquired penetration contact due to infected 'sharps', or forcible penetration in rape
How to thank TFD for its existence? Tell a friend about us, add a link to this page, add the site to iGoogle, or visit webmaster's page for free fun content.
| ?Page tools | ||
|---|---|---|
|