Now, researchers have developed a new method that can look at a specific segment of DNA and pinpoint a single mutation, which could help diagnose and treat diseases such as cancer and tuberculosis.
This conceptual image shows probe and target complexes at different stages of the reaction that checks for mutations. The red dots represent mutations in a target base pair, while sequences with illuminated green lights indicate that no mutation was found in the reaction.
Credit: Yan Liang, L2XY2.com
These small changes can be the root of a disease or the reason some infectious diseases resist certain antibiotics. The findings were published online this week (July 28) in the journal Nature Chemistry.
"We've really improved on previous approaches because our solution doesn't require any complicated reactions or added enzymes, it just uses DNA," said lead author Georg Seelig, a University of Washington assistant professor of electrical engineering and of computer science and engineering. "This means that the method is robust to changes in temperature and other environmental variables, making it well-suited for diagnostic applications in low-resource settings."
DNA is a type of nucleic acid, the biological molecule that gives all living things their unique genetic signatures. In a double strand of DNA, known as a double helix, a series of base pairs bond and encode our genetic information. As genomics research has progressed, it's clear that a change of just one base pair – a sequence mutation, an insertion or a deletion – is enough to trigger major biological consequences. This could explain the onset of disease, or the reason some diseases don't respond to usual antibiotic treatment.
Take, for example, tuberculosis – a disease that's known to have drug-resistant strains. Its resistance to antibiotics often is due to a small number of mutations in a specific gene. If a person with tuberculosis isn't responding to treatment, it's likely because there is a mutation, Seelig said.
Now, researchers have the ability to check for that mutation preventatively.
Seelig, along with David Zhang of Rice University and Sherry Chen, a UW doctoral student in electrical engineering, designed probes that can pick out mutations in a single base pair in a target stretch of DNA. The probes allow researchers to look in much more detail for variations in long sequences – up to 200 base pairs – while current methods can detect mutations in stretches of up to only 20.
"In terms of specificity, our research suggests that we can do quadratically better, meaning that whatever the best level of specificity, our best will be that number squared," said Zhang, an assistant professor of bioengineering at Rice University.
The testing probes are designed to bind with a sequence of DNA that is suspected of having a mutation. The researchers do this by creating a complimentary sequence of DNA to the double-helix strand in question. Then, they allow molecules containing both sequences to mix in a test tube in salt water, where they naturally will match up to one another if the base pairs are intact. Unlike previous technologies, the probe molecule checks both strands of the target double helix for mutations rather than just one, which explains the increased specificity.
The probe is engineered to emit a fluorescent glow if there's a perfect match between it and the target. If it doesn't illuminate, that means the strands didn't match and there was in fact a mutation in the target strand of DNA.
The researchers have filed a patent on the technology and are working with the UW Center for Commercialization. They hope to integrate it into a paper-based diagnostic test for diseases that could be used in parts of the world with few medical resources.
The research was funded by the National Institutes of Health, the National Science Foundation and the Department of Defense's Advanced Research Projects Agency.
For more information, contact Seelig at firstname.lastname@example.org.
Michelle Ma | EurekAlert!
20.11.2017 | Washington University in St. Louis
Carefully crafted light pulses control neuron activity
20.11.2017 | University of Illinois at Urbana-Champaign
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
20.11.2017 | Life Sciences
20.11.2017 | Trade Fair News
20.11.2017 | Earth Sciences