Oct. 19, 2009 (The Korea Times) — By Kim Tong-hyung
Staff Reporter
Scientists have decoded the genome of bacteria, claiming a major advancement in research into how its evolution works.
In a study published in peer-review journal Nature, a group of multinational researchers said they sequenced the genomes sampled through 40,000 generations from a laboratory population of coliform bacteria.
The research was aimed at adding detail to the elusive picture of the relationship between the rates of genomic evolution and the adaption by living organisms.
The Nature researchers insisted that obtaining genome sequences from experimentally evolving populations may offer an opportunity to trace this relationship with precision.
“The research offers a significant improvement in predicting the regularity of evolution across genomic changes occurring over hundreds of thousands of generations,” said Kim Ji-hyun, a researcher from the Korea Research Institute of Bioscience and Biotechnology (KRIBB) and who participated in the recent research, which was the result of nearly 20 years of collaboration.
Other key authors of the Nature paper were Richard Lenski of the United States’ Michigan State University and Dominique Schneider of France’s Universite Joseph Fourier.
“The advancement in the techniques handling micro-organisms also presents significant economic potential as these may prove difference makers in biotechnology. The findings from this research could be used to produce fundamental technologies in synthetic biology,” Kim said.
The researchers, who conducted experiments on the fitness of each bacteria generation throughout the long-term project, found the relationship between evolution rates and adaptation to be inconsistent. Although adaptation decelerated sharply, genomic evolution was nearly constant for 20,000 generations.
Such clock-like regularity is usually viewed as the signature of neutral evolution, but several lines of evidence indicate that almost all of these mutations were beneficial, the scientists wrote in their Nature study.
The mutations that occurred in the protein parts of the bacteria were all connected to changes in amino-acid sequences, the scientists said.
“This same population later evolved at an elevated mutation rate and accumulated hundreds of additional mutations dominated by a neutral signature,” the scientists wrote in the Nature paper.
“The coupling between genomic and adaptive evolution is complex and can be counterintuitive even in a constant environment. (OTCBB:CTEV) In particular, beneficial substitutions were surprisingly uniform over time, whereas neutral substitutions were highly variable.”
Source: The Korea Times (October 19, 2009 – 9:07 PM EDT)
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