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:7/10/2014)... a microbial megacity, teeming with life too small to ... types of bacteria can be found. Now scientists ... their own daily cyclesnot unlike the residents of a ... and eat at the same times., What,s more, it,s ... solar energy to help them photosynthesize food from inorganic ...
(Date:7/10/2014)... Ben-Gurion University of the Negev scientists have discovered that ... warm up before the evening hunt. , As ... to regulate,their internal temperature. The researchers believe that this ... to increase their body temperature before they leave their ... trapping the wild large-clawed scorpions ( Scorpio maurus palmatus ...
(Date:7/10/2014)... 2014 Amyloid diseases, such as Alzheimer,s disease, ... all share the common trait that proteins aggregate ... in vitro studies have found that neither the ... very toxic. New evidence using two-dimensional infrared (2D ... the amylin aggregation pathway that may explain toxicity, ...
Breaking Biology News(10 mins):New research finds ocean's most abundant organisms have clear daily cycles 2New research finds ocean's most abundant organisms have clear daily cycles 3Scorpions are master architects, according to new research from Ben-Gurion University 2New technology reveals insights into mechanisms underlying amyloid diseases 2
... Tampa, Fla. (June 1, 2010) The sugar-alcohol ... cord blood cells injected into neonatal rat models of ... the University of South Florida. The mannitol opened the ... that make up the barrier. Intravenously-delivered human umbilical ...
... International Institute for Species Exploration at Arizona State University names ... year. The list for 2009 was published to coincide with ... Carl Linnaeus. It contains only two new plant species, one ... of the Linnean Society . Nepenthes attenboroughii ...
... New treatments for malaria are possible after Walter and Eliza ... drug heparin can stop malaria from infecting red blood cells. ... is transmitted by mosquitoes. The most common form of malaria ... burrows into red blood cells where it rapidly multiplies, leading ...
Cached Biology News:Mannitol boosts effectiveness of potential cord blood treatment for cerebral palsy in lab animals 2Rare carnivorous plant on top 10 list of newly discovered species 2Blood-thinning copycat enters malaria fight 2
Other biology definitionOther Tags