Definition

Noun: A recessive gene is a type of gene that will only be expressed in an organism's observable traits (its phenotype) when two identical copies of it are present. This means an individual must inherit the recessive gene from both parents for the trait it carries to be visible. If a dominant gene is paired with it, the dominant gene's trait will be expressed instead, and the recessive gene's trait will be hidden.

Usage

A recessive gene is discussed in the context of genetics and inheritance. - It is often contrasted with a dominant gene. - The concept is fundamental for understanding inherited characteristics and genetic disorders.

Examples

Advanced Usage

• Carrier: An individual who has one copy of a recessive gene and one copy of a dominant gene. They do not show the trait themselves but can pass the recessive gene to their offspring.
  • He is a carrier for the sickle cell trait, meaning he has one normal gene and one recessive gene.
• Autosomal Recessive: A pattern of inheritance where the recessive gene is located on a non-sex chromosome (autosome). Many genetic disorders follow this pattern.
  • Phenylketonuria (PKU) is an autosomal recessive disorder.

Variants and Related Words

• Recessive (Adjective): Describing the gene or the trait it produces.
  • Blue eye color is a recessive trait.
• Recessive Allele: A more technical term synonymous with "recessive gene." An allele is a variant form of a gene.
• Dominant Gene (Antonym): A gene that is expressed even when only one copy is present.

Synonyms

• Recessive allele
• Recessive factor (less common in modern usage)

Related Concepts (Not Phrasal Verbs or Idioms)

• Punnett Square: A diagram used to predict the probability of offspring inheriting specific genotypes, including combinations involving recessive genes.
• Genotype vs. Phenotype: The genotype is the genetic makeup (e.g., having two recessive genes), while the phenotype is the observable result (e.g., blue eyes).
• Homozygous Recessive: The genetic condition of having two identical recessive alleles for a particular gene.

Noun

1. gene that produces its characteristic phenotype only when its allele is identical
   • the recessive gene for blue eyes