An obscure swatch of human DNA once thought to be nothing more than biological trash may actually offer a treasure trove of insight into complex genetic-related diseases such as cancer and diabetes, thanks to a novel sequencing technique developed by biologists at Texas A&M University.
The game-changing discovery was part of a study led by Texas A&M biology doctoral candidate John C. Aldrich and Dr. Keith A. Maggert, an associate professor in the Department of Biology, to measure variation in heterochromatin. This mysterious, tightly packed section of the vast, non-coding section of the human genome, widely dismissed by geneticists as "junk," previously was thought by scientists to have no discernable function at all.
In the course of his otherwise routine analysis of DNA in fruit flies, Aldrich was able to monitor dynamics of the heterochromatic sequence by modifying a technique called quantitative polymerase chain reaction (QPCR), a process used to amplify specific DNA sequences from a relatively small amount of starting material. He then added a fluorescent dye, allowing him to monitor the fruit-fly DNA changes and to observe any variations.
Aldrich's findings, published today in the online edition of the journal PLOS ONE, showed that differences in the heterochromatin exist, confirming that the junk DNA is not stagnant as researchers originally had believed and that mutations which could affect other parts of the genome are capable of occurring.
"We know that there is hidden variation there, like disease proclivities or things that are evolutionarily important, but we never knew how to study it," Maggert said. "We couldn't even do the simplest things because we didn't know if there was a little DNA or a lot of it.
"This work opens up the other non-coding half of the genome."
Maggert explains that chromosomes are located in the nuclei of all human cells, and the DNA material in these chromosomes is made up of coding and non-coding regions. The coding regions, known as genes, contain the information necessary for a cell to make proteins, but far less is known about the non-coding regions, beyond the fact that they are not directly related to making proteins.
"Believe it or not, people still get into arguments over the definition of a gene," Maggert said. "In my opinion, there are about 30,000 protein-coding genes. The rest of the DNA -- greater than 90 percent -- either controls those genes and therefore is technically part of them, or is within this mush that we study and, thanks to John, can now measure. The heterochromatin that we study definitely has effects, but it's not possible to think of it as discrete genes. So, we prefer to think of it as 30,000 protein-coding genes plus this one big, complex one that can orchestrate the other 30,000."
Although other methods of measuring DNA are technically available, Aldrich notes that, as of yet, none has proven to be as cost-effective nor time-efficient as his modified-QPCR-fluorescence technique.
"There's some sequencing technology that can also be used to do this, but it costs tens of thousands of dollars," Aldrich said. "This enables us to answer a very specific question right here in the lab."
The uncharted genome sequences have been a point of contention in scientific circles for more than a decade, according to Maggert, a Texas A&M faculty member since 2004. It had long been believed that the human genome -- the blueprint for humanity, individually and as a whole -- would be packed with complex genes with the potential to answer some of the most pressing questions in medical biology.
When human DNA was finally sequenced with the completion of the Human Genome Project in 2003, he says that perception changed. Based on those initial reports, researchers determined that only two percent of the genome (about 21,000 genes) represented coding DNA. Since then, numerous other studies have emerged debating the functionality, or lack thereof, of non-coding, so-called "junk DNA."
Now, thanks to Aldrich's and Maggert's investigation of heterochromatin, the groundwork has been laid to study the rest of the genome. Once all of it is understood, scientists may finally find the root causes and possibly treatments for many genetic ailments.
"There is so much talk about understanding the connection between genetics and disease and finding personalized therapies," Maggert said. "However, this topic is incomplete unless biologists can look at the entire genome. We still can't -- yet -- but at least now, we're a step closer."
About Research at Texas A&M University: As one of the world's leading research institutions, Texas A&M is in the vanguard in making significant contributions to the storehouse of knowledge, including that of science and technology. Research conducted at Texas A&M represents annual expenditures of more than $820 million. That research creates new knowledge that provides basic, fundamental and applied contributions resulting in many cases in economic benefits to the state, nation and world. To learn more, visit http://research.tamu.edu.
Chris Jarvis, (979) 845-7246 or
or Dr. Keith A. Maggert, (979) 845-6610
Chris Jarvis | newswise
Platinum nanoparticles for selective treatment of liver cancer cells
15.02.2019 | ETH Zurich
New molecular blueprint advances our understanding of photosynthesis
15.02.2019 | DOE/Lawrence Berkeley National Laboratory
For the first time, an international team of scientists based in Regensburg, Germany, has recorded the orbitals of single molecules in different charge states in a novel type of microscopy. The research findings are published under the title “Mapping orbital changes upon electron transfer with tunneling microscopy on insulators” in the prestigious journal “Nature”.
The building blocks of matter surrounding us are atoms and molecules. The properties of that matter, however, are often not set by these building blocks...
Scientists at the University of Konstanz identify fierce competition between the human immune system and bacterial pathogens
Cell biologists from the University of Konstanz shed light on a recent evolutionary process in the human immune system and publish their findings in the...
Laser physicists have taken snapshots of carbon molecules C₆₀ showing how they transform in intense infrared light
When carbon molecules C₆₀ are exposed to an intense infrared light, they change their ball-like structure to a more elongated version. This has now been...
The so-called Abelian sandpile model has been studied by scientists for more than 30 years to better understand a physical phenomenon called self-organized...
Physicists from the University of Basel have developed a new method to examine the elasticity and binding properties of DNA molecules on a surface at extremely low temperatures. With a combination of cryo-force spectroscopy and computer simulations, they were able to show that DNA molecules behave like a chain of small coil springs. The researchers reported their findings in Nature Communications.
DNA is not only a popular research topic because it contains the blueprint for life – it can also be used to produce tiny components for technical applications.
11.02.2019 | Event News
30.01.2019 | Event News
16.01.2019 | Event News
15.02.2019 | Physics and Astronomy
15.02.2019 | Physics and Astronomy
15.02.2019 | Life Sciences