Jason Mick (Blog) - October 4, 2010 8:20 AM
"They're promiscuous little bastards" -- Professor John Paul on bacteria's use of gene-transfer agents
Chemical, geological, and genetic evidence points to life originating on Earth 3.5 to 3.8 billion years ago (BYA).
At the time the Earth was less than a billion years old and was quite a hostile place to live. One key effort to understanding how nature created life is to explain how life survived such a hostile environment. Recent studies suggest that RNA-based lifeforms may have preceded DNA-based lifeforms. In order to avoid degradation, RNA likely formed in cool environments -- like ice pockets, or, more likely, cool northern ocean waters (which would be less likely to freeze through).
Gene-transfer-agents are used by bacteria to transfer useful evolutions to each other.
(Source: University of Hamburg)
Another question is how early life developed such a vast array of chemical tools, with which to conquer its new world and transform via the process of evolution into wondrous multicellular beasts. According to a new study, the answer may lie with virus-like particles called gene-transfer agents (GTAs).
GTAs typically consist of a 3 to 4 kilobase pair (kbp) fragment of the host organism's chromosome, wrapped in a protein coat. The little particles can have a big impact on microbial life, allow bacteria to "team up" and transfer key genes to each other.
A new study shows that GTAs may transfer genes at 1,000 to 100 million times the previously estimated rate, indicating they may have been a critical factor in early evolution.
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Read more here/Leia mais aqui: Daily Tech
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Science 1 October 2010:
Vol. 330. no. 6000, p. 50
DOI: 10.1126/science.1192243
BREVIA
High Frequency of Horizontal Gene Transfer in the Oceans
Lauren D. McDaniel,1,* Elizabeth Young,1 Jennifer Delaney,1 Fabian Ruhnau,2 Kim B. Ritchie,3John H. Paul1
Oceanic bacteria perform many environmental functions, including biogeochemical cycling of many elements, metabolizing of greenhouse gases, functioning in oceanic food webs (microbial loop), and producing valuable natural products and viruses. We demonstrate that the widespread capability of marine bacteria to participate in horizontal gene transfer (HGT) in coastal and oceanic environments may be the result of gene transfer agents (GTAs), viral-like particles produced by -Proteobacteria. We documented GTA-mediated gene transfer frequencies a thousand to a hundred million times higher than prior estimates of HGT in the oceans, with as high as 47% of the culturable natural microbial community confirmed as gene recipients. These findings suggest a plausible mechanism by which marine bacteria acquire novel traits, thus ensuring resilience in the face of environmental change.
1 University of South Florida College of Marine Science, St. Petersburg, FL 33701, USA.
2 University of Duisburg-Essen, Biofilm Centre, 47057 Duisburg, Germany.
3 Center for Coral Reef Research, Mote Marine Laboratory, Sarasota, FL 34236, USA.
* To whom correspondence should be addressed. E-mail: mcdaniel@marine.usf.edu
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