‘Junk’ DNA helps in quick adaptation to environmental changes

May 29th, 2009 - 1:47 pm ICT by IANS  

London, May 29 (IANS) The unknown side of the DNA, dismissed as “junk”, activates our genomic evolution, tuning gene activity and helping organisms adapt to environmental changes quickly, a new study has found.
“Most people do not realise that all our genes only comprise about three percent of the total human genome. The rest is basically one large black box,” said Kevin Verstrepen, of the Flanders Institute for Biotechnology, (VIB), who headed the research.

Scientists used to suspect most of the DNA outside of genes, the so-called “non-coding DNA”, is useless trash that has sneaked into our genome and refuses to leave.

One commonly known example of such “junk DNA” are the so-called tandem repeats, short stretches of DNA that are repeated head-to-tail.

“At first sight, it may seem unlikely that this stutter-DNA has any biological function,” said Marcelo Vinces, the study’s co-author. “On the other hand, it seems hard to believe that nature would foster such a wasteful system.”

The team of scientists found that stretches of tandem repeats influence the activity of neighbouring genes. To further test their theory, researchers conducted a complex experiment aimed at mimicking biological evolution, using yeast cells as Darwinian guinea pigs, said a VIB release.

Their results show that when a repeat is present near a gene, it is possible to select yeast mutants that show vastly increased activity of this gene. However, when the repeat region was removed, this fast evolution was impossible.

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