Re: News: 'Telepathic' Genes Recognize Similarities In Each Other

In article <fnle0v$2cq7$1@xxxxxxxxxxxxxxxxxxx>, "Robert Karl Stonjek" <rstonjek@xxxxxxxxxxxxxx> wrote:
'Telepathic' Genes Recognize Similarities In Each Other
ScienceDaily (Jan. 26, 2008) - Genes have the ability to recognise
similarities in each other from a distance, without any proteins or other
biological molecules aiding the process, according to new research. This
discovery could explain how similar genes find each other and group together
in order to perform key processes involved in the evolution of species.

This new study shows that genes -- which are parts of double-stranded DNA
with a double-helix structure containing a pattern of chemical bases - can
recognise other genes with a similar pattern of chemical bases.

This ability to seek each other out could be the key to how genes identify
one another and align with each other in order to begin the process of
'homologous recombination' -- whereby two double-helix DNA molecules come
together, break open, swap a section of genetic information, and then close
themselves up again.

Recombination is an important process which plays a key role in evolution
and natural selection, and is also central to the body's ability to repair
damaged DNA. Before now, scientists have not known exactly how suitable
pairs of genes find each other in order for this process to begin.

The authors of the new study carried out a series of experiments in order to
test the theory, first developed in 2001 by two members of this team, that
long pieces of identical double-stranded DNA could identify each other
merely as a result of complementary patterns of electrical charges which
they both carry. They wanted to verify that this could indeed occur without
physical contact between the two molecules, or the facilitating presence of
proteins.

Previous studies have suggested that proteins are involved in the
recognition process when it occurs between short strands of DNA which only
have about 10 pairs of chemical bases. This new research shows that much
longer strands of DNA with hundreds of pairs of chemical bases seem able to
recognise each other as a whole without protein involvement. According to
the theory, this recognition mechanism is stronger the longer the genes are.

The researchers observed the behaviour of fluorescently tagged DNA molecules
in a pure solution. They found that DNA molecules with identical patterns of
chemical bases were approximately twice as likely to gather together than
DNA molecules with different sequences.

Professor Alexei Kornyshev from Imperial College London, one of the study's
authors, explains the significance of the team's results: "Seeing these
identical DNA molecules seeking each other out in a crowd, without any
external help, is very exciting indeed. This could provide a driving force
for similar genes to begin the complex process of recombination without the
help of proteins or other biological factors. Our team's experimental
results seem to support these expectations."

Understanding the precise mechanism of the primary recognition stage of
genetic recombination may shed light on how to avoid or minimise
recombination errors in evolution, natural selection and DNA repair. This is
important because such errors are believed to cause a number of genetically
determined diseases including cancers and some forms of Alzheimer's, as well
as contributing to ageing. Understanding this mechanism is also essential
for refining precise artificial recombination techniques for biotechnologies
and gene therapies of the future.

The team is now working on a set of further experiments to determine exactly
how these interactions work, including the predicted length dependence. In
addition, further studies are needed to ascertain whether this interaction,
discovered in a test tube, occurs in the highly complex environment of a
living cell.

The study was carried out by researchers at Imperial College London and the
National Institute of Health (NIH) in the USA. The work was funded in the UK
by the EPSRC and supported by the NIH Institute of Child Health and Human
Development.

Journal reference: Geoff S. Baldwin, Nicholas J. Brooks, Rebecca E. Robson,
Aaron Wynveen, Arach Goldar, Sergey Leikin, John M. Seddon, and Alexei A.
Kornyshev. 'DNA Double Helices Recognize Mutual Sequence Homology in a
Protein Free Environment', Journal of Physical Chemistry B, 23 January 2008.

Although the two guys who came up with this theory are among the
smartest people I personally came across when doing my graduate work,
they are still physicists and I think the relevance of this finding to the real
life phenomena is quite dubious.

DNA at high concentration in 0.5M salt in the presence of 10-15% PEG
in small volume over two weeks! That's quite clearly designed to push the
limit of its solubility (in fact, plasmids precipitate quantitatively under
these conditions). So, we are basically talking about partitioning or even
phase separation, both one step removed from crystallization. Physics of it
notwithstanding (a bit obscure at this point), there is hardly any surprise
that DNA molecules tend to slowly segregate to the ones most similar
to them.

When lysozyme is induced to crystallize out of egg white in the presence
of many other proteins, any claim that lysozyme "recognizes itself"
(formally correct) must be met with a degree of scepticism when it comes
to biological relevance.

DK

.

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  • News: Telepathic Genes Recognize Similarities In Each Other
    ... 'Telepathic' Genes Recognize Similarities In Each Other ... similarities in each other from a distance, without any proteins or other ... biological molecules aiding the process, ... This new study shows that genes -- which are parts of double-stranded DNA ...
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  • News: Telepathic genes recognise similarities in each other.
    ... without any proteins or other biological molecules aiding ... similar genes find each other and group together in order to perform ... DNA with a double-helix structure containing a pattern of chemical ... bases - can recognise other genes with a similar pattern of chemical ...
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  • Re: Whats more important, self-organzation or evolution?
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