Paradoxo: bactéria "antiga" com genes codificando proteínas "modernas"

Um artigo interessante. O PDF pode ser baixado gratuitamente aqui.

The Paradox of the "Ancient" Bacterium Which Contains "Modern" Protein-Coding Genes
Heather Maughan*, C. William Birky Jr.*, Wayne L. Nicholson*, William D. Rosenzweig and Russell H. Vreeland

*Graduate Interdisciplinary Program in Genetic
Department of Ecology and Evolutionary Biology,
Department of Veterinary Science and Microbiology, University of Arizona; and Department of Biology, West Chester University

The isolation of microorganisms from ancient materials and the verification that they are as old as the materials from which they were isolated continue to be areas of controversy. Almost without exception, bacteria isolated from ancient material have proven to closely resemble modern bacteria at both morphological and molecular levels. This fact has historically been used by critics to argue that these isolates are not ancient but are modern contaminants introduced either naturally after formation of the surrounding material (for further details, see Hazen and Roeder 2001Citation and the reply by Powers, Vreeland, and Rosenzweig 2001Citation ) or because of flaws in the methodology of sample isolation (reviewed recently in Vreeland and Rosenzweig 2002Citation ).

Such criticism has been addressed experimentally by the development of highly rigorous protocols for sample selection, surface sterilization, and contamination detection and control procedures. Using the most scrupulous and well-documented sampling procedures and contamination-protection techniques reported to date, Vreeland, Rosenzweig, and Powers (2000)Citation reported the isolation of a sporeforming bacterium, Bacillus strain 2-9-3, from a brine inclusion within a halite crystal recovered from the 250-Myr-old Permian Salado Formation in Carlsbad, NM.