Linkage Analysis
- Identifies chromosomal regions by comparing a trait’s inheritance pattern to known genetic markers.
- Applied to both family pedigrees and larger population studies.
- Used to locate genes for conditions like Huntington’s disease (chromosome 4) and for complex traits such as height or intelligence.
Definition
Section titled “Definition”Linkage analysis is a method used in genetics to identify the chromosomal location of a gene or group of genes associated with a particular trait or disease by examining the inheritance patterns of that trait or disease in a family or population and comparing them to known genetic markers on the chromosomes.
Explanation
Section titled “Explanation”Linkage analysis examines how a trait or disease co-segregates with known genetic markers across generations or among individuals in a population. When a marker and a genetic locus are inherited together more often than expected by chance, they are considered linked, which narrows the chromosomal region likely to contain the causal gene(s). This approach can be applied to familial cases—tracing inheritance within a family—or to broader studies across many individuals to locate chromosomal regions associated with a trait.
Examples
Section titled “Examples”Familial disease example
Section titled “Familial disease example”A family with a history of a rare genetic disorder, Huntington’s disease, which is caused by a mutation in a specific gene on chromosome 4, can be studied using linkage analysis. Researchers examine the inheritance patterns of the disease in the family and compare them to known genetic markers on chromosome 4 to identify the gene’s chromosomal location.
Complex-trait example
Section titled “Complex-trait example”To identify genes associated with complex traits such as height or intelligence, researchers may study a large population and compare inheritance patterns of the trait to known genetic markers on the chromosomes. By analyzing these data, chromosomal regions associated with the trait can be identified, potentially leading to the genes responsible for the trait.
Use cases
Section titled “Use cases”- Identifying the genetic basis of traits and diseases by locating chromosomal regions linked to those traits.
- Providing insights that enable further research and potential treatments based on the located genes.
Related terms
Section titled “Related terms”- Genetic markers
- Chromosomal regions
- Inheritance patterns