dominance

The state of being dominant.

- cerebral d. the fact that one hemisphere is dominant over the other and will exercise greater influence over certain functions; the left cerebral hemisphere is usually dominant in the control of speech, language and analytical processing, and mathematics, while the right hemisphere (usually nondominant) processes spatial concepts and language as related to certain types of visual images; handedness (right-handed people have left cerebral d.) is considered a general example of cerebral d..

- false d. SYN: quasidominance.

- genetic d. denoting a pattern of inheritance of an autosomal mendelian trait due to a gene that always manifests itself phenotypically; generally, the phenotype in the homozygote is more severe than in the heterozygote, but details depend on what criterion of phenotyping is used.

- d. of traits 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.

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dom·i·nance 'däm(-ə)-nən(t)s n the fact or state of being dominant: as

a) the relative position of an individual in a social hierarchy compare PECKING ORDER

b) the property of one of a pair of alleles or traits that suppresses expression of the other in the heterozygous condition

c) functional asymmetry between a pair of bodily structures (as the right and left hands)

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dom·i·nance (domґĭ-nəns) [L. dominari to govern] 1. the state of being dominant. 2. in genetics, the phenotypic expression of a gene in both heterozygotes and homozygotes; see also Mendel's laws, under law. See also codominance and quasidominance. 3. in coronary artery anatomy, the state of supplying the posterior diaphragmatic part of the interventricular septum and the diaphragmatic surface of the left ventricle. In 85 percent of the population, the right coronary artery is dominant; in the remainder, the left coronary artery is dominant.