Definition

1. Noun (Genetics): An allele that expresses its phenotypic effect even when heterozygous with a recessive allele; it produces the same phenotype whether its paired allele is identical or different.

Usage

• The dominant allele is represented by an uppercase letter (e.g., 'B' for brown eyes).
• In a genetic cross, the trait determined by the dominant allele will appear in the offspring if at least one copy is present.

Examples

• Noun:
  • The gene for brown eye color has a dominant allele.
  • If a plant inherits the dominant allele for tallness, it will be tall even if it also carries the allele for shortness.

Advanced Usage

• "To be dominant over": Describes the relationship where one allele masks the effect of another.
  • In pea plants, the allele for round seeds is dominant over the allele for wrinkled seeds.

Variants and Related Words

• Dominance (n): The phenomenon where one allele masks the expression of another.
  • The principle of dominance is a key part of Mendelian genetics.
• Dominant gene (n): Often used synonymously with 'dominant allele' in non-technical contexts.
  • The dominant gene for freckles is common in their family.

Synonyms

• Dominant gene (in common parlance)
• Dominant factor (in a broader genetic context)

Related Phrases

• Express a dominant allele: To show the trait controlled by that allele.
  • The offspring will express the dominant allele if they inherit it from either parent.
• Carry a dominant allele: To possess the allele, which may or may not be expressed phenotypically depending on the other allele.
  • Both parents carry the dominant allele for the trait.

Related Concepts (Not Idioms)

• Recessive allele: The allele whose effect is masked by a dominant allele in a heterozygous pair.
• Homozygous dominant: Having two identical copies of the dominant allele.
• Heterozygous: Having one dominant and one recessive allele for a gene.

Noun

1. an allele that produces the same phenotype whether its paired allele is identical or different