Definition

1. Adjective:
   • Genetics: Describing a gene, trait, or condition that is determined by a gene located on a sex chromosome (typically the X chromosome). Its inheritance pattern differs between males and females because the number of X chromosomes differs between the sexes.

Usage

• The term is used primarily in biology and genetics to describe the pattern of inheritance for specific characteristics.
• It modifies nouns like "gene," "trait," "disorder," "characteristic," or "inheritance."
• Example: "The gene for red-green color blindness is sex-linked."

Examples

• Adjective:
  • Hemophilia is a well-known sex-linked disorder.
  • In fruit flies, the gene for white eyes is a sex-linked recessive trait.
  • The sex-linked inheritance pattern explains why the condition appears more frequently in males.

Advanced Usage

• Sex-linked recessive: This is the most common type of sex-linked inheritance. A female needs two copies of the recessive allele (one on each X chromosome) to express the trait, while a male only needs one copy (on his single X chromosome). This is why conditions like Duchenne muscular dystrophy are much more common in males.
• X-linked: Often used synonymously with "sex-linked," as the vast majority of sex-linked genes are located on the X chromosome. "X-linked" is sometimes considered more precise.
• Y-linked: Refers to traits determined by genes on the Y chromosome. These are also technically sex-linked but are much rarer and are inherited exclusively from father to son.

Variants and Related Words

• Sex linkage (noun): The phenomenon or the pattern of inheritance itself.
  • Example: "The sex linkage of the trait was discovered through pedigree analysis."
• X-linked (adjective): A more specific synonym for the most common form of sex-linked inheritance.
• Y-linked (adjective): Referring to genes on the Y chromosome.

Synonyms

• X-linked (in most common contexts)

Antonyms

• Autosomal: Referring to genes located on any chromosome that is not a sex chromosome (autosomes). Autosomal traits are inherited with equal probability by males and females.

Adjective

1. concerning characteristics that are determined by genes carried on the sex chromosomes (on the X chromosome in particular)