The process behind RNA interference takes place inside cells, when RNA molecules are degraded by corresponding RNAi sequences that have the effect of silencing specific genes.This technique of silencing genes was first used for targeting specific genes. Now, researchers have developed a library of RNAi sequences that can be used in genome-wide screening methods for a number of organisms.Today, RNAi screening is seen as an attractive area of development for the future of genetic screening, but there is a need for new expertise in this area if it is to move forward in a practical sense.
How does it compare to Classic Genetic Screening Techniques?
There are similarities in the methodologies used for RNAi and other classic genetic techniques, including large-scale screening and targeted hits. A difference, though, might be which phenotypes are scored.The drawbacks and promises would be similar in both cases due to the fact that RNAi screening uses forward genetics with techniques that are reversed.
• Advantages
- The RNAi technique opens up new possibilities for genetic screening in previously immune specimens such as human cells.
- The sequences to the genes that are identified from this type of screening are known straightaway and any harmful mutations can be identified more easily, as there is no need to recover them. This all helps towards achieving a more refined analysis of the genes that are discovered.
- This type of screening has the promise to be more efficient and have greater potential.
- Redundancies can be found by targeting a number of genes that are connected in sequence.
• Disadvantages
- The knockdown technique can sometimes produce results that are variable and incomplete.
- Classic genetic techniques, in the past, have allowed researchers to reveal regulatory mechanisms through identifying alleles that reveal these processes. RNAi cannot achieve this as it is a gene suppressing technique.
- Some genes can’t be screened by this RNAi screening due to their resistance.
- Knocking down protein effectively is difficult due to their long half-lives.
Conclusion
RNAi screening has established itself as a standard tool in the experimental screening field. Thanks to the growth of the RNAi library and the setting-up of centres for screening, which can automate the process, it is now possible for laboratories to carry-out genome-wide screenings on a wide scale. Screening, however, requires accurate assays, which should be remembered when talking of the efficient and speedy benefits of RNAi methods.Going forward, the RNAi screening process is predicted to be just the start of a wider field of analysis in biology.
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There are a number of ways a disease-causing virus or bacteria can be modified in order to make it useful as part of a vaccine, each with their own strengths and limitations. The exact method used varies from vaccine to vaccine, depending upon various factors, including the traits of the disease itself.
Modification Strategies
Viruses can be weakened, limiting their potential to reproduce within the human body, but still triggering the body’s immune response. This then protects against future infection. Vaccines for measles, mumps and chickenpox are made this way, but these vaccines are not usually suitable for people who already have weakened immune systems.Another option is to inactivate or kill a virus, using a chemical. This means that the virus cannot possibly reproduce within the body, or cause disease and a number of vaccines are created through this strategy, including hepatitis A, rabies and polio. However, a limitation is that several doses are usually required to achieve immunity.
Other vaccines are developed by using a small part of the virus or bacteria which causes disease, such as its protein. Hepatitis B and tetanus vaccines are made in this way and a benefit is that they can be given to people who already have weakened immune systems, although like with inactivated viruses, several doses may be necessary.