Connect with us

PERSONAL HEALTH

Researchers mix RNA and DNA to study how life’s process began billions of years ago

Published

on

From: Scripps

RNA World is a fascinating theory, says Ramanarayanan Krishnamurthy, PhD, an associate professor of chemistry at Scripps Research, but it may not hold true. The problem is that the ingredients, such as enzymes, to make RNA World work just didn’t exist on early Earth.

“RNA World has given rise to the idea that if you somehow synthesize RNA, which can replicate and catalyze reactions, everything else automatically follows,” says Krishnamurthy, who is a member of the Simons Collaboration on the Origins of Life and holds a joint appointment with the Center for Chemical Evolution, co-funded by the NASA Astrobiology program and the National Science Foundation. “That’s not the case, because RNA World relies on RNA replicating itself, which is very difficult.”

Part of the challenge is that RNA molecules form stable structures called duplexes. These structures have what’s known as a strong binding affinity. This means the RNA molecules have difficulty separating from each other and acting as templates for replicating further in the absence of enzymes.

Krishnamurthy now has experimental evidence to demonstrate that life’s process on Earth could have actually started with molecules that looked like a mixture of RNA and DNA. In the latest issue of Nature Chemistry, he and the study’s first author, Subhendu Bhowmik, PhD, also of Scripps Research, report that these mixed molecules form unstable duplexes and have lesser affinity for themselves. Surprisingly, these “chimeras” have stronger affinity for RNA and DNA, which allows them to act as templates for making RNA or DNA.

In fact, the researchers were able to form these chimeras under lab conditions and show that they have the potential to replicate RNA and DNA, and the thus formed RNA and DNA are able to reproduce the chimeras. This behavior could lead to a cross-catalytic amplification of RNA and DNA—a key step toward the evolution of complex organisms.

“A provocative implication of this study is that RNA and DNA could have appeared simultaneously instead of the widely accepted RNA World theory, where RNA appears first and then gives rise to DNA,” says Krishnamurthy. “This means mixtures of RNA and DNA could have co-existed.”

In organisms today, DNA and RNA perform very different roles in our cells. The new project experimentally supports the idea that life could have arisen from a much messier system, where “pure” RNA and DNA did not exist yet. As Krishnamurthy says: “It’s OK not to have clean chemistry.”

In work spearheaded by Bhowmik, a research associate in Krishnamurthy’s Scripps Research laboratory, the team also created “heterogeneous” mixed molecules made of RNA and a synthetic molecule called TNA, which has been proposed to be a plausible ancestor of RNA (“pre-RNA”). TNA is very similar to RNA, but scientists have replaced one type of sugar molecule (ribose) with another (threose). This allows TNA to cross-pair with RNA and DNA. Krishnamurthy and Bhowmik say a molecule like TNA could have performed this cross-pairing at the very beginning of evolution, leading to the side-by-side formation of TNA and RNA.

By mixing RNA-DNA, the researchers showed that it could have been possible to form a mixed molecule that could work as templates for RNA and DNA. This mixed molecule is also a high-energy system in the sense that it forms unstable duplexes. The new research shows that these unstable duplexes (higher energy systems) are capable of giving rise to RNA and DNA, which form more stable duplexes (lower energy systems). Thus, there is a thermodynamically favorable movement from chimeric systems (less-stable, higher-energy) to homogeneous systems (more-stable, lower-energy).

“Hybrid system like these could have helped in the evolution of homogeneous systems,” says Bhowmik.

We’ll never know exactly how early life formed, but the experiments at least show chemical reactions that could have eventually led to the pure RNA and DNA sequences that support life today. The work also supports the findings of a 2018 Scripps Research study, which showed how an engineered bacterium can function with a mixed RNA-DNA genome.

Krishnamurthy says research going forward should focus on which ingredients needed for RNA-DNA chimeras would have been available on prebiotic Earth. The scientists used several molecules that were likely not available back then, though similar ingredients should have existed. The new study gives researchers a “proof of principle” that these reactions can work, and Krishnamurthy plans to follow up with further experiments to explore the pathways for how life’s molecules could have come together. “This study is the first step in that direction,” he says.

Krishnamurthy is also interested in how RNA-DNA chimeras might be used in medicinal chemistry studies. He says these mixed systems may help researchers overcome some challenges in genetic sequencing.

The study, “The role of sugar-backbone heterogeneity and chimeras in the simultaneous emergence of RNA and DNA,” was supported by NASA (grant NNX14AP59G), the Simons Foundation (grant 327124) and a NASA Astrobiology Postdoctoral Program fellowship.

Source: Scripps

Continue Reading

The Daily Do It

 

 

The News without the Noise

The Great Transition4 days ago

Understanding the Great Transition

The Great Transition4 days ago

Information, Communications, Media

The Great Transition4 days ago

Consumption, Materials and Resources

The Great Transition4 days ago

Food and Agriculture

The Great Transition4 days ago

Transforming Health

The Great Transition4 days ago

Education for a New World

Featured4 days ago

The Transformation of Energy and Transportation Systems

The Great Transition2 weeks ago

Going forward: A realistic action plan

Rethink X4 weeks ago

Understanding where we’re at and how to get to where we are going

Video: Rethink4 weeks ago

0:00 / 20:59 Rethinking Energy 2020-2030: 100% Solar, Wind, and Batteries is Just the Beginning

Policy4 weeks ago

NO TO NUKES: Non-proliferation treaty conference ends in failure, ban treaty shows the way forward

Innovation without borders1 month ago

Innovation without Borders

Innovation without borders1 month ago

Information without Borders

Innovation without borders1 month ago

Affordable and Renewable Clean Energy

Innovation without borders1 month ago

Resources and Materials

Innovation without borders1 month ago

Improved Food Systems

Build for Change1 month ago

Why Endless Consumption of Our Finite Planet Will Take Us to Our Cliff of Doom and How We Can Prevent It

Featured1 month ago

Indigenous rice out-performs commercial varieties in nutrition value and tolerance to drought, flood, extreme weather

FOOD + AG.1 month ago

Reviving Jordan’s community, resilience and food sovereignty through urban wheat cultivation

FOOD + AG.1 month ago

An organic farming revolution in Thailand

Mobilized TV1 month ago

Heart Attacks Are Not Worth Dying For

Mobilized TV1 month ago

Rethink: Humanity’s Next Operating System

Mobilized TV1 month ago

Find out how your community could take on big business to serve the health of all.

Food and Land1 month ago

Understanding the Roots of the Food Crises and Preventing Future Crises: Resilience and a Deep Dive

Editorials2 months ago

Another Conference is not going to save us:

A web of Life for ALL Life2 months ago

Truths or Consequences

Build for Change2 months ago

The launch of “Rights of the Atlantic Ocean” campaign in Newfoundland

Build for Change2 months ago

What’s really going on in the Brazilian Rainforests?

Editorials2 months ago

To Save the Planet, Forget About the Globe (And Act Locally)

Weekly Exchanges2 months ago

A global information commons

Build for Change2 months ago

We are One

Build for Change2 months ago

The Power of us

Build for Change2 months ago

When Stars Collide

Build for Change2 months ago

Heal the World

People Planet Purpose2 months ago

A NEW STORY FOR A NEW WORLD

Rethink X4 weeks ago

Understanding where we’re at and how to get to where we are going

Video: Rethink4 weeks ago

0:00 / 20:59 Rethinking Energy 2020-2030: 100% Solar, Wind, and Batteries is Just the Beginning

Rethink X4 months ago

Out of Chaos Comes Creation: Understanding Transformation of Civilizations

Rethink X4 months ago

Understanding the Repeating Patterns of History: Growth / Collapse / Transformation

Mobilized News Network7 months ago

Clarity Above all Else

Paradigm Change7 months ago

Nuremberg Prosecutor at 102: Make Law, Not War.

INTERVIEWS8 months ago

GAIA TALKS: The Earth Speaks: Mohamed Ismail from Egyptians Abroad For Democracy Worldwide

Paradigm Change8 months ago

An Empowered World: People, we are Ready!

Paradigm Change8 months ago

Conscious capitalism and Raising the Bar of Human Possibility

Paradigm Change8 months ago

Open Collaboration on an Epic Scale: The Future is Cooperatively Decentralized

Paradigm Change8 months ago

Transforming Energy and Transportation

Paradigm Change8 months ago

Transforming agriculture and food systems for optimal planetary and personal health

Arts9 months ago

How The Pentagon and CIA Have Shaped Thousands of Hollywood Movies into Super Effective Propaganda

A web of Life for ALL Life10 months ago

We are One

Mobilized TV10 months ago

How we can eradicate heart Disease

Mobilized TV10 months ago

Howard Bloom: Imagination Takes You Everywhere

Featured10 months ago

From Punk to Planet: Slam Dunk the Junk with Dave Street

Mobilized TV11 months ago

A Moral Responsibility: Jean Su, Ctr. for Biological Diversity

Mobilized TV11 months ago

On Free Speech TV: Rethinking Humanity with James Arbib of RethinkX

Mobilized TV11 months ago

Sustainable Architecture, Design and Building for a Sustainable Planet

Mobilized TV11 months ago

A better understanding of lawn care for Climate Care featuring Dr. Rob Moir of the Ocean River Institute

Mobilized TV11 months ago

Stories from the Reservation: Davidica Little Spotted Horse

Translate »