Question

Define linkage.

Answer 1

• 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 into different chromatids during the chromosomal crossover and are therefore said to be more linked than markers that are far apart.
• In other words, the nearer two genes are on a chromosome, the lower the chance of recombination between them, and the more likely they are to be inherited together. Markers on different chromosomes are perfectly unlinked. The typical unit of genetic linkage is the centimorgan (cM).
• A distance of 1 cM between two markers means that the markers are separated into different chromosomes on average once per 100 meiotic products, thus once per 50 meiosis.