Definition

1. Noun:
   • A gene that expresses its phenotypic effect even when heterozygous with a recessive allele: A dominant gene is one that produces its characteristic trait or phenotype in an organism regardless of whether it is paired with an identical allele or a different (recessive) one. It masks the effect of a recessive gene.

Usage and Examples

• Noun:
  • The presence of a single dominant gene is enough to produce brown eyes.
  • In pea plants, the gene for round seeds is a dominant gene over the gene for wrinkled seeds.
  • Genetic counselors can explain the probability of inheriting a dominant gene for a particular condition.

Advanced Usage

• "To be carried by a dominant gene": To be determined or caused by a dominant allele.
  • The condition is carried by a dominant gene, so only one parent needs to pass it on for a child to be affected.

Variants and Related Words

• Dominant allele (n): Another term for a dominant gene; the variant form of a gene that is expressed over a recessive allele.
  • The dominant allele for seed shape produces round seeds.
• Dominance (n): The phenomenon in genetics where one allele (the dominant one) masks the expression of another allele (the recessive one).
  • Mendel's law of dominance explains the behavior of dominant genes.

Synonyms

• Expressed gene: A gene whose trait is visibly or measurably present in the organism.
• Masking allele: An allele that overrides the phenotypic expression of its paired allele.

Related Phrases and Concepts

• Autosomal dominant: A pattern of inheritance where a dominant gene is located on an autosome (non-sex chromosome).
  • Huntington's disease is an example of an autosomal dominant disorder.
• Incomplete dominance: A genetic situation where neither allele is completely dominant, resulting in a blended phenotype. (This is a related but distinct concept from a simple dominant gene).
  • In snapdragons, red and white flower color alleles show incomplete dominance, producing pink flowers.

Idioms and Common Expressions

(This term is highly technical and specific to genetics, so it is not commonly used in idiomatic expressions outside of scientific contexts.)

Noun

1. gene that produces the same phenotype in the organism whether or not its allele identical
   • the dominant gene for brown eyes