Positional cloning

Positional Cloning

Positional cloning, also known as Map-based cloning, is a technique used in genetics to identify and locate the position of genes associated with a particular phenotype. This method is often used when the nature of the gene is unknown, and only the approximate location is known.

Overview

Positional cloning involves the use of linkage analysis to map the location of a gene. This is done by studying the inheritance patterns of genetic markers that are located near the gene of interest. Once the location of the gene is determined, it can be isolated and studied.

Process

The process of positional cloning involves several steps:

1. Identification of a phenotype that is likely to be caused by a single gene.
2. Collection of genetic material from individuals who exhibit the phenotype and their relatives.
3. Analysis of the genetic material to identify markers that are linked to the phenotype.
4. Narrowing down the location of the gene by studying recombination events.
5. Isolation and sequencing of the gene.
6. Confirmation of the gene's role in the phenotype by studying its function in model organisms.

Applications

Positional cloning has been used to identify many genes associated with human diseases, including Cystic fibrosis, Huntington's disease, and Breast cancer. It has also been used in plant breeding to identify genes associated with desirable traits.

Limitations

While positional cloning is a powerful tool, it has some limitations. It requires a large sample size and is time-consuming. It also assumes that the phenotype is caused by a single gene, which is not always the case.

See also

• Genetic linkage
• Genetic marker
• Genome sequencing

Positional cloning Resources
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