Genetic map

Genetic map or linkage map is a type of genetic analysis that shows the position of genes and genetic markers relative to each other on a chromosome. The greater the frequency that two gene loci are inherited together, the smaller the distance between them on the map.

Overview

A genetic map is not a physical map (such as a chromosome map). While physical maps measure the physical distance between gene loci, genetic maps are based on the genetic linkage information. The units of a genetic map are centimorgans (cM), named after the American geneticist Thomas Hunt Morgan.

Construction of a Genetic Map

The construction of a genetic map involves the following steps:

1. Collection of genetic markers: These are genes or DNA sequences with a known location on a chromosome that can be used to identify individuals or species. They can be described as variations which can be observed.
2. Genotyping: The process of determining differences in the genetic make-up (genotype) of an individual by examining the individual's DNA sequence using biological assays and comparing it to another individual's sequence or a reference sequence.
3. Analysis of recombination frequency: The frequency of recombination is the number of recombinant offspring divided by the total number of offspring. It is used to determine the distance between two genes on a genetic map.

Uses of Genetic Maps

Genetic maps are used in many different ways:

• They can help scientists understand and treat diseases by identifying genes that cause or contribute to diseases.
• They can be used in plant and animal breeding to help select for traits of interest.
• They can help scientists understand the evolution and migration of different species.

See Also

• Genome
• Genetic linkage
• Genetic marker
• Genetic variation
• Genotyping
• Recombination frequency

References

Genetic map Resources
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