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16.2: Genetic Screens

JoVE Core
Molecular Biology

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Genetic Screens

16.2: Genetic Screens

Genetic screens are tools used to identify genes and mutations responsible for phenotypes of interest. Genetic screens help identify individuals or a group of people at risk of developing  genetic diseases and help them with early intervention, targeted therapy, and reproductive options.

Forward genetic screens

Forward or “classical” genetic screens involve creating random mutations in an organism’s DNA using radiation, mutagens, or insertion of additional bases, which result in visible changes in the phenotype. The mutant is inbred to obtain progenies that are homozygous for the mutation. The mutation and its associated phenotype are identified, and gene locus on the chromosome are mapped.

Reverse genetic screens

Reverse genetic screens involve disruption of known genes, followed by screening for mutant phenotypes resulting from these manipulations. Expression screening is a type of reverse genetic screen that involves vector libraries containing the protein-coding sequences of various genes extracted from the genome of an organism or environmental samples. These screens help in the identification of novel proteins. For example, in zebrafish, using reverse genetic screening, the genes involved in early development are identified.


Genetic screens have several applications, such as identifying protein interactions, characterizing gene-drug interactions, and understanding the cause of diseases. For example, a mutant yeast library generated using large-scale random mutagenesis with transposon insertions can be grown in the presence of a drug. The effect of the drug on each mutant can be analyzed using PCR followed by microarrays or sequencing analysis. Similarly, screens can be used for the analysis of genes and molecular networks disrupted in human disease. For example, genes involved in neurodegenerative diseases can be identified by culturing neurons in the presence of RNA-encoding viruses to knock down the expression of different target genes. Cells can then be immunostained and analyzed to detect physical abnormalities and identify genes responsible.

Suggested Reading


Genetic Screens Genes Mutations Phenotypes Genetic Diseases Early Intervention Targeted Therapy Reproductive Options Forward Genetic Screens Classical Genetic Screens Random Mutations Phenotype Mutant Inbred Gene Locus Chromosome Mapping Reverse Genetic Screens Disruption Of Known Genes Screening For Mutant Phenotypes Expression Screening Vector Libraries Protein-coding Sequences Novel Proteins Zebrafish Early Development Applications Protein Interactions Gene-drug Interactions Cause Of Diseases

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