Earth's Own Mars, the Atacama Desert Yields Amazing Extremophile Microbes 63
A University of Colorado-Boulder team has uncovered extremophile microbes in the rocky, high-altitude Atacama desert on the Chile-Argentina border "which seem to have a different way of converting energy than their cousins elsewhere in the world." According to the researchers, "[T]hese are very different than anything else that has been cultured. Genetically, they’re at least 5 percent different than anything else in the DNA database of 2.5 million sequences." It's an exciting frontier for biologists in part because of the recurring interest in the possibility that life has existed (or does exist) on Mars; the dry, volcanic Atacama is often compared to the Martian surface.
BS comparison (Score:5, Informative)
the dry, volcanic Atacama is often compared to the Martian surface.
Except that it has an ozone layer protecting it, and the surface isn't covered by free radicals ready to destroy anything organic.
There is nowhere on Earth that is comparable to the surface of Mars. There is no life on the surface of Mars. There might be life under the surface, but that is a completely different comparison.
Link to actual article (Score:5, Informative)
Why press releases like this fail to link the actual article is beyond me - surely that helps the research to be more widely read.
http://www.agu.org/pubs/crossref/pip/2012JG001961.shtml
(abstract is free, fulltext behind paywall)
Re:Didn't we hear about this a year ago? (Score:5, Informative)
The "arsenic based bacteria" which were supposed to revolutionize the way we viewed biology didn't even turn out to be a hoax, but bad science. Although, after RTFA, it looks as if these scientists are being a bit more cautious before making outrageous declarations.
Biologists are finding fascinating new microorganisms in harsh environments all the time - this is mostly very good science, but nothing revolutionary or remotely controversial. The microbes in TFA are interesting because there isn't an obvious energy source available (since they're non-photosynthetic). This means that they may have evolved some unique metabolic strategy. But there is no inherent reason why these microbes can't or shouldn't exist; they're just something we haven't seen before.
The arsenic bacteria article was immediately controversial because for the claims of the authors were true, it would directly conflict with some very basic chemical phenomena, and didn't make sense in light of everything else we know about cellular biochemistry. (The mere existence of microbes in such high levels of arsenic is intrinsically interesting, since they would have had to evolve tolerance for what is effectively a poison, but again hardly revolutionary.) It was doubly controversial because it didn't do a very good job experimentally supporting the primary claim, that the bacteria preferred arsenate to phosphate in nucleic acid backbones. If you're going to put forward such an extreme hypothesis, you need to really nail the evidence 100%. The hand-waving science-by-press-release was an added slap in the face. Every scientist (especially the great ones) loves a bit of PR now and again - that's why universities issue press releases like TFA - but you have to know your limits.
Re:BS comparison (Score:5, Informative)
I used to do extremophile research. I can chip in a little knowledge about microbial research to neutralize some of this sensationalism
Ribosomal RNA sequences are often the basis for speciation in biology. And while the human and ape species may be less than 1 percent difference, they are described to be different species. The full genomic DNA seqs may have more difference.
With microbes, the rRNA threshold for a different species is 13%. There are species of E.coli that have 50% less genomic DNA (meaning beyond 50% different since they already are missing half), that are called E.coli because the rRNA is not varied enough (less than 13% different).
My point is that in the world of microbes, and furthermore extremophiles, a 5% difference is not much. That may be a sensational news point. I persnally genetically identified several organisms from the Boiling Springs Lake Microbial Observatory (65-95 deg C, pH 1.7) that were 11-12.7% different than previously described species....
Re:BS comparison (Score:4, Informative)