Linkage analysis

Linkage analysis is a genetic method that searches for chromosome segments that co-segregate with the inheritance of a disease phenotype. This method is used to map genes on chromosomes and to estimate the distance between genes. The principle of linkage analysis is based on the observation that genes that are physically close on a chromosome tend to be inherited together.

History

The concept of linkage analysis was first introduced by Thomas Hunt Morgan in the early 20th century. Morgan and his students studied the inheritance of traits in fruit flies and discovered that certain traits tend to be inherited together, suggesting that the genes controlling these traits are linked on the same chromosome.

Method

Linkage analysis involves the study of the co-segregation of traits in families. The method is based on the observation that the closer two genes are on a chromosome, the less likely they are to be separated during meiosis, a process that shuffles genes between chromosomes. By studying the patterns of inheritance of traits in families, researchers can estimate the distance between genes and map their relative positions on chromosomes.

Applications

Linkage analysis has been used to map many human disease genes, including those for Huntington's disease, cystic fibrosis, and Duchenne muscular dystrophy. The method has also been used to map genes in other organisms, including plants and animals.

Limitations

While linkage analysis is a powerful tool for gene mapping, it has several limitations. The method requires large families with multiple affected individuals, which are often difficult to find. In addition, linkage analysis can only provide an estimate of the relative position of genes, not their exact location.

See also

• Genetic linkage
• Genetic mapping
• Genome-wide association study
• Quantitative trait locus

Linkage analysis Resources
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