from the world's big
'One among millions': DNA is not the only genetic molecule
A recent computer analysis found that millions of possible chemical compounds could be used to store genetic information. This begs the question — why DNA?
- The central dogma of biology states that genetic information flows from DNA to RNA to proteins, but new research suggests that this may not be the only way for life to work.
- A sophisticated computer analysis revealed that millions of other molecules could be used to function in place of the two nucleic acids, DNA and RNA.
- The results have important implications for developing new drugs, the origins of life on Earth, and its possible presence in the rest of the universe.
Simply put, the so-called central dogma of biology asserts that genetic information flows from DNA to RNA to proteins, and once that information is passed to a protein, it cannot be returned as DNA or RNA again. It's dubbed the central dogma because it seems to be universal amongst all living organisms. There are some exceptions to the linear flow described in the popular version of the central dogma — information can be passed back and forth between RNA and DNA or between DNA and DNA or RNA and RNA, but the central players remain the same: DNA, RNA, and proteins.
But what if this didn't have to be the case? Could genetic information be stored in media other than the two nucleic acids of DNA and RNA? New research published in the Journal of Chemical Information and Modeling suggests that there might not be just a handful of alternative molecules for storing genetic information, but millions.
Millions of useful targets
The central dogma of biology asserts that the genetic information is transcribed from DNA to RNA, which then translates that information into useful products like proteins. This new research, however, suggests that DNA and RNA are just two options out of millions of others.
Analogues to nucleic acids exist, many of which serve as the foundation for important drugs for treating viruses like HIV and hepatitis as well as for treating cancers, but until recently, no one was sure of how many unknown nucleic acid analogues could be out there.
"There are two kinds of nucleic acids in biology," said co-author Jim Cleaves, "and maybe 20 or 30 effective nucleic acid-binding nucleic acid analogues. We wanted to know if there is one more to be found or even a million more. The answer is, there seem to be many more than was expected."
Cleaves and colleagues decided to conduct a chemical space analysis — in essence, a sophisticated computer technique that generates all possible molecules that adhere to a set of defined criteria. In this case, the criteria were to find compounds that could serve as nucleic acid analogues and as a means of storing genetic information.
"We were surprised by the outcome of this computation," said co-author Markus Meringer. "It would be very difficult to estimate a priori that there are more than a million nucleic acid–like scaffolds. Now we know, and we can start looking into testing some of these in the lab."
Though no specific analogues were targeted in this paper, it does present a long list of candidates to be explored for use as drugs for serious diseases like HIV or cancer. A more intriguing possibility suggested by the research is that life itself may have taken its very first steps using one of these alternative compounds.
Many scientists believe that before DNA became the dominant means of storing genetic information, life used RNA to code genetic data and pass it down to offspring. In part, this is because RNA can directly produce proteins, which DNA can't do on its own, and because it's a simpler structure than DNA. Over time, life likely started to opt for using DNA for storage due to its greater stability and to rely on RNA as a kind of middleman for producing proteins. But RNA on its own is still a very complicated compound and is fairly unstable; in all likelihood, something simpler came before RNA, possibly using some of the nucleic acid analogues identified in this study.
A galaxy of nucleic acid analogues
Not only does this shed light on how life may have started on Earth, but it also has implications for alien life as well. Co-author Jay Goodwin said, "It is truly exciting to consider the potential for alternate genetic systems based on these analogous nucleosides — that these might possibly have emerged and evolved in different environments, perhaps even on other planets or moons within our solar system. These alternate genetic systems might expand our conception of biology's 'central dogma' into new evolutionary directions, in response and robust to increasingly challenging environments here on Earth."
When we search for extraterrestrial life, often we're looking for signs of RNA and DNA, but this may be an excessively narrow scope. After all, if millions of alternatives exist, there would need to be something very special indeed for life to universally favor using just DNA and RNA.
Sallie Krawcheck and Bob Kulhan will be talking money, jobs, and how the pandemic will disproportionally affect women's finances.
Men take longer to clear COVID-19 from their systems; a male-only coronavirus repository may be why.
- A new study found that women clear coronavirus from their systems much faster than men.
- The researchers hypothesize that high concentrations of ACE2-expressing cells in the testes may store more coronavirus.
- There are many confounding factors to this mystery—some genetic, others social and behavioral.
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A laboratory technician at Queen Elizabeth University Hospital, Glasgow, holds a container of test-tube samples from people tested for novel coronavirus.
Further research required<div class="rm-shortcode" data-media_id="z9vH49bb" data-player_id="FvQKszTI" data-rm-shortcode-id="7ef1ab8ca2f90b28543d580c408ed25f"> <div id="botr_z9vH49bb_FvQKszTI_div" class="jwplayer-media" data-jwplayer-video-src="https://content.jwplatform.com/players/z9vH49bb-FvQKszTI.js"> <img src="https://cdn.jwplayer.com/thumbs/z9vH49bb-1920.jpg" class="jwplayer-media-preview" /> </div> <script src="https://content.jwplatform.com/players/z9vH49bb-FvQKszTI.js"></script> </div> <p>The Montefiore-Einstein study is currently preliminary, and further research will be required before researchers can determine what, if anything, its results illuminate.</p><p>The study is currently published on <em>Medrxiv</em>, a <a href="https://www.aje.com/arc/benefits-of-preprints-for-researchers/" target="_blank">preprint</a> distributor. This means the study has been shared publicly before undergoing the <a href="https://undsci.berkeley.edu/article/howscienceworks_16" target="_blank">peer-review process</a>.</p><p>Preprints allow researchers to communicate their findings before official publication, which can take months if not a year or longer. This pre-publication can lead to early feedback, increased visibility, and new collaborations. It's especially helpful for <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6400415/" target="_blank">early-career researchers</a> trying to establish themselves.</p><p>However, given the speed at which coronavirus is spreading, researchers have leaned on preprints as a means of disseminating data to other experts faster than the peer review allows. As a result, <em>Medrixiv</em> has seen a <a href="https://www.nytimes.com/2020/04/14/science/coronavirus-disinformation.html" target="_blank">surge of preprint studies</a>, but they must be read within the context of their preliminary status.</p><p>The Montefiore-Einstein also has its limitations. The study had an initial sample size of only 68 subjects (48 males, 20 females) and a further examination of three families. And the connection of coronavirus to ACE2 enzymes in the testes came from database research, not direct observation.</p><p>The researchers acknowledge the need for further investigation. In particular, Shastri stresses the need to confirm the coronavirus's ability to infect and multiply in testicular tissue. If other researchers find their data promising, they could move forward with new research to build upon the study and see if this clue fits into the mystery.</p>
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Coronavirus protesters in Los Angeles. Men are more likely than women to disregard health warnings from officials.
The word "learning" opens up space for more people, places, and ideas.
- The terms 'education' and 'learning' are often used interchangeably, but there is a cultural connotation to the former that can be limiting. Education naturally links to schooling, which is only one form of learning.
- Gregg Behr, founder and co-chair of Remake Learning, believes that this small word shift opens up the possibilities in terms of how and where learning can happen. It also becomes a more inclusive practice, welcoming in a larger, more diverse group of thinkers.
- Post-COVID, the way we think about what learning looks like will inevitably change, so it's crucial to adjust and begin building the necessary support systems today.
The coronavirus pandemic has brought out the perception of selfishness among many.
- Selfish behavior has been analyzed by philosophers and psychologists for centuries.
- New research shows people may be wired for altruistic behavior and get more benefits from it.
- Crisis times tend to increase self-centered acts.