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Fwd = Lightning provides vital spark for evolution

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  • Frits Westra
    Forwarded by: fwestra@hetnet.nl (Frits Westra) URL: http://www.newscientist.com/news/news.jsp?id=ns99991102 Original Date: 2 Aug 2001
    Message 1 of 1 , Aug 2 1:24 PM
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      Forwarded by: fwestra@... (Frits Westra)
      URL: http://www.newscientist.com/news/news.jsp?id=ns99991102
      Original Date: 2 Aug 2001 13:21:32 -0000

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      NewScientist.com

      The World's No.1 Science & Technology News Service

      Lightning provides vital spark for evolution

      19:00 01 August 01
      Scott Norris

      Bolts of lightning that strike the ground may help bacteria adapt and
      evolve. Experiments suggest that electrical currents help soil
      bacteria exchange DNA.

      Scientists commonly use electricity to increase the permeability of
      bacterial cell membranes, making it easier to insert DNA. Now Sandrine
      Deman�che's team at the University of Lyon has provided the first
      evidence that nature may have been wise to this trick all along.

      The researchers seeded soil samples with the E. coli bacterium, as
      well as fragments of DNA containing genes for antibiotic resistance.
      They zapped the soil with a simulated lightning strike, and found that
      many of the bacteria had acquired the resistance genes.

      Bacteria are already known to take up and use foreign DNA released
      into the environment when other organisms die. Scientists knew this
      "horizontal gene transfer" occurs naturally in soil, but thought it
      was relatively rare. However, recent genomic research indicates that
      this gene take-up is widespread and has played a major role in the
      evolution of the bacterial genome.

      "This result might help explain the discrepancy between the very low
      observed rates of gene transfer and the apparently wide distribution
      of DNA sequences among bacteria," says team member Timothy Vogel.

      Lightning may seem relatively rare, but there are about a hundred
      flashes a second around the planet. Ground strikes almost always
      create currents in the surrounding soil similar to those from the
      simulated bolts, Vogel says.

      Journal reference: Applied and Environmental Microbiology (vol 67, p
      3440)

      19:00 01 August 01


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