Navigation Links
Reverse genetics


Reverse genetics is an approach to discovering the function of a gene that proceeds oppositely to how such discoveries typically unfold in classical genetics, or in forward genetics.

Classical and reverse genetics are alike in that, by either approach, investigators typically must deduce the function of a normal gene from the effects that follow from damaging or changing it. Otherwise, the two approaches contrast. By the classical approach, geneticists first look for rare individuals with unusual traits or phenotypes, and then they trace these traits to an underlying faulty allele or gene. Locating the gene on its chromosome is the end point of an investigation.

With the readily performed modern techniques of DNA sequencing and as a result of the sequencing of many whole genomes, many genetic sequences are discovered in advance of any other information about them. To learn the influence a sequence has on phenotype, or to discover its biological function, researchers may engineer a change or disruption in it -- by site-directed mutagenesis, for example, by deletion of a gene by gene knockout (as can be done in some organisms, such as yeast and mice) -- and only afterwards look for the effect of such alterations in the whole organism. The discovery of gene silencing using double stranded RNA, also known as RNA interference (RNAi), and the development of gene knockdown using Morpholino oligos have made disrupting gene expression an accessable technique for many more investigators. So phenotype, rather than the starting point, is in reverse genetics the end point.

An alternative used in organisms such as C. elegans is to randomly induce DNA deletions and select for deletions in a gene of interest. Deletions have been created in every non-essential gene in the yeast genome.

Another reverse genetics technique is the application of RNA interference. RNAi creates a specific knockout effect without actually mutating the DNA of interest. In C. elegans, RNAi has been used to systematically interfere with the expression of most genes in the genome.

While RNA interference relies on systems within the cell for efficacy (e.g. the dicer proteins, the RISC complex) a simple alternative for gene knockdown is Morpholino antisense oligos. While RNAi acts by directing cellular systems to degrade target messenger RNA (mRNA), Morpholinos bind and block access to the target mRNA without requiring the activity of cellular proteins and without necessarily accelerating mRNA degradation. Morpholinos are effective is systems ranging in complexity from cell-free translation in a test tube to humans.

Finally, a more difficult genetics technique is the creation of transgenic organisms that overexpress a gene of interest. The resulting phenotype may reflect the normal function of the gene.


'"/>


(Date:10/29/2014)... City on September 19, 2014, leading geneticist and humanitarian ... Genome Sciences and Medicine at the University of Washington ... Tel Aviv University, was awarded the 2014 Lasker-Koshland Special ... her honorary degree from TAU, Prof. King was the ... and for the past 18 years she has been ...
(Date:10/29/2014)... reveals new research potential of the Barcode of ... in the Biodiversity Data Journal ... format and imported these into a human-readable text developed ... (PWT). Data were used to study the species distributions ... Microgastrinae subfamily. , BOLD is originally designed to support ...
(Date:10/29/2014)... international Cancer Genomics of the Kidney consortium ( ... cancer and exposure to aristolochic acid, an ingredient ... Nature Communications , have important implications for ... 140,000 people every year, and in Central Europe ... of the International Cancer Genome Consortium (ICGC), has ...
Breaking Biology News(10 mins):Geneticist and humanitarian: Prof. Mary-Claire King receives Lasker Award 2Go straight and publish: From Barcode of Life Data Systems to scholarly publishing systems 2Kidney cancer in Central Europe 2
... (June 28 2013) A study carried out in India ... bone marrow stem cells in patients with type 2 ... when compared to a control group of TD2M patients ... , The study appears as an early e-publication for ...
... make a big difference. A "left-handed" molecule of a ... its mirror-image "right-handed" counterpart could be completely inactive. That,s ... crucial: Living organisms are made only from left-handed amino ... Now, a team of scientists at the U.S. ...
... the late spring, the 4000 elk of the Clarks ... following the greening grass into the highlands of the ... on vegetation fed by snowmelt. It,s a short trip ... uncommonly free of roads, fences, metropolitan areas, and other ...
Cached Biology News:Type 2 diabetes patients transplanted with own bone marrow stem cells reduces insulin use 2Tiny nanocubes help scientists tell left from right 2Tiny nanocubes help scientists tell left from right 3Declining fortunes of Yellowstone's migratory elk 2Declining fortunes of Yellowstone's migratory elk 3Declining fortunes of Yellowstone's migratory elk 4
Other biology definitionOther Tags