Genes can Seek Out Their ‘relatives’ Without Help

by Medindia Content Team on  January 25, 2008 at 4:59 PM Genetics & Stem Cells News   - G J E 4
Genes can Seek Out Their ‘relatives’ Without Help
A new find could help explain the mechanism that enables genes to find each other and group together. This is in order to perform key processes involved in the evolution of species.

The discovery could also be helpful in explaining the mechanism that enables genes to find each other and group together in order to perform key processes involved in the evolution of species. Understanding this mechanism may also help to find out how genetic disorders like Alzheimer's disease are caused.

The study demonstrates 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 particular skill of seeking each other out could explain how genes identify one another and align with each other to kick start the process of 'homologous recombination', whereby two double-helix DNA molecules come together, break open, exchange a section of genetic information, and then close again.

Recombination is a pivotal process playing a key role in evolution and natural selection, and is also vital to the body's ability to repair damaged DNA. Until now, it was not known exactly how suitable pairs of genes find each other in order to facilitate this process.

For the study, a series of experiments were carried out in order to test the theory, first developed in 2001 stating 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.

The researchers wanted to verify that this could also occur without physical contact between the two molecules, or the facilitating presence of proteins.

Earlier studies have indicated that proteins are involved in the recognition process when it occurs between short strands of DNA having only about 10 pairs of chemical bases.

The new research shows that it sis possible for much longer strands of DNA having hundreds of pairs of chemical bases to recognise each other as a whole without protein involvement. According to the theory, this recognition mechanism is stronger the longer the genes are.

After observing the behaviour of fluorescently tagged DNA molecules in a pure solution, the researchers found that DNA molecules with identical patterns of chemical bases were almost twice as likely to gather together as DNA molecules with different sequences.

"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," explained Professor Alexei Kornyshev from Imperial College London, one of the study's authors.

This understanding of the exact 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 study is published in the recent issue of Journal of Physical Chemistry B.

Source: ANI

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