Linked gene

Linked genes are genes that are located close together on the same chromosome and tend to be inherited together. This concept is a fundamental aspect of genetic linkage, a key principle in the field of genetics.

Overview

The concept of linked genes was first proposed by Thomas Hunt Morgan in the early 20th century. Morgan discovered that some genes do not follow the principle of independent assortment, postulated by Gregor Mendel, which states that the alleles of different genes segregate, or separate, independently of each other during meiosis. Instead, Morgan found that genes located close together on the same chromosome tend to be inherited together, a phenomenon he termed genetic linkage.

Genetic Linkage

Genetic linkage is the tendency of DNA sequences that are close together on a chromosome to be inherited together during the meiosis phase of sexual reproduction. Two genetic markers that are physically near to each other are unlikely to be separated onto different chromatids during chromosomal crossover, and are therefore said to be more linked than markers that are far apart.

Linkage Map

A linkage map is a genetic map of a species or experimental population that shows the position of its known genes or genetic markers relative to each other, rather than a specific physical distance along each chromosome. Linkage maps are created by finding the genetic locus of traits that are caused by single genes, and by using genetic recombination to determine the relative position between the genes.

Linkage Disequilibrium

Linkage disequilibrium is the non-random association of alleles at different loci in a given population. Loci are said to be in linkage disequilibrium when the frequency of association of their different alleles is higher or lower than what would be expected if the loci were independent and associated randomly.

See Also

• Genetic recombination
• Chromosomal crossover
• Genetic mapping
• Mendelian inheritance