| 释义 |
Recessive trait dom·i·nance of traitsan expression of the apparent physiologic relationship existing between two or more genes that may occupy the same chromosomal locus (alleles). At a specific locus there are three possible combinations of two allelic genes, A and a: two homozygous (AA and aa) and one heterozygous (Aa). If a heterozygous individual presents only the hereditary characteristic determined by gene A, but not a, A is said to be dominant and a recessive; in this case, AA and Aa, although genotypically distinct, should be phenotypically indistinguishable. If AA, Aa, and aa are distinguishable, each from the others, A and a are codominant.dom·i·nance of traits (dom'i-năns trāts) An expression of the apparent physiologic relationship existing between two or more genes that may occupy the same chromosomal locus (alleles). At a specific locus there are three possible combinations of two allelic genes, A and a: two homozygous (AA and aa) and one heterozygous (Aa). If a heterozygous individual presents only the hereditary characteristic determined by gene A, but not a, A is said to be dominant and a recessive; in this case, AA and Aa, although genotypically distinct, should be phenotypically indistinguishable. If AA, Aa, and aa are distinguishable, each from the others, A and a are codominant. Recessive traitAn inherited trait that is outwardly obvious only when two copies of the gene for that trait are present—as opposed to a dominant trait where one copy of the gene for the dominant trait is sufficient to display the trait. The recessive condition is said to be masked by the presence of the dominant gene when both are present; i.e., the recessive condition is seen only in the absence of the dominant gene.Mentioned in: Cutis Laxa, Galactosemia, Glucose-6-Phosphate Dehydrogenase Deficiency, Pseudoxanthoma Elasticum |