Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

DNA downloads alone

05.02.2002


Two million years ago life looked like this. Four billion years ago it was a different story.
© SPL


The information in DNA can be copied into new molecules without proteins’ help.

Chemists have reproduced the basic process of information transfer central to all life without the catalysts that facilitate it in living cells1.

They show that DNA alone can pass its message on to subsequent generations. Many researchers believe that DNA-like molecules acted thus to get life started about four billion years ago - before catalytic proteins existed to help DNA to replicate.



The experiment, carried out by David Lynn and co-workers at Emory University in Atlanta, Georgia, might create a new basis for the precise synthesis of useful polymer materials. It may even hasten the advent of synthetic biology: the creation of life from scratch.

History repeats itself

Synthetic self-replicating molecules have been made in the lab at least three times before. But in all these cases the replicating molecules were given a substantial helping hand.

Before, each molecule acted as a template on which its copy was constructed from two ready-made halves. In other words most of the information in the copy was present already in the fragments from which it was made. It was rather like reproducing the information in this sentence simply by pasting it together from two already-written halves.

In contrast, Lynn and colleagues paste each letter in place, one by one. They make, not a copy, but a complementary molecule, containing the same information but in a different code. It is rather like making a copy of one of these sentences but translated into French.

In the cell, DNA itself contains two such complementary molecules, each one a chain of molecular units, stuck together in the double helix. When DNA replicates before a cell divides, these complementary strands part and each acts as a template to guide the synthesis of a fresh strand.

Each DNA strand contains all the information needed to make a new strand. There are four different kinds of molecular unit, and the sequence of these along the strand determines the sequence of units assembled in the new strand. Enzymes drive this assembly process.

Stranded

Lynn’s group has found a way to do without the enzymes, so that a single strand of DNA can act as a template for the assembly of its complementary strand. Scientists have achieved this before, but imperfectly: only one of the four types of DNA unit acted as a template, and the complementary strand wasn’t always the same length as the template.

The Emory group uses a new trick to join the components together on a DNA template. The chemical links between successive units in the new strand aren’t like those in DNA itself. Instead they are amide linkages, like those that unite proteins’ molecular units, which are also chain-like molecules laden with information. This makes the assembly of the new strand more accurate.

Amide-linked DNA chains can help units of true DNA to join together. So the researchers hope to achieve the reverse process of templating DNA using amide-linked DNA. This might then enable the two kinds of molecule to support their mutual replication, allowing the possibility of molecular evolution and the appearance of life-like complexity.

References

  1. Li, X., Zhan, Z.-Y. J., Knipe, R. & Lynn, D. G. DNA-catalyzed polymerization. Journal of the American Chemical Society, 124, 746 - 747, (2002).


PHILIP BALL | © Nature News Service
Further information:
http://www.nature.com/nsu/020204/020204-2.html

More articles from Life Sciences:

nachricht Could this protein protect people against coronary artery disease?
17.11.2017 | University of North Carolina Health Care

nachricht Microbial resident enables beetles to feed on a leafy diet
17.11.2017 | Max-Planck-Institut für chemische Ökologie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

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...

Im Focus: Visual intelligence is not the same as IQ

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...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

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....

Im Focus: Researchers Develop Data Bus for Quantum Computer

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,...

Im Focus: Wrinkles give heat a jolt in pillared graphene

Rice University researchers test 3-D carbon nanostructures' thermal transport abilities

Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

NASA detects solar flare pulses at Sun and Earth

17.11.2017 | Physics and Astronomy

NIST scientists discover how to switch liver cancer cell growth from 2-D to 3-D structures

17.11.2017 | Health and Medicine

The importance of biodiversity in forests could increase due to climate change

17.11.2017 | Studies and Analyses

VideoLinks
B2B-VideoLinks
More VideoLinks >>>