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Actinobacteria were last universal common ancestor (LUCA)?

From “Actinobacteria as the Base of the Evolutionary Tree” (Science Daily, July 26, 2012), we learn,

Paleontological, biochemical, and genomic studies have produced conflicting versions of the evolutionary tree. Now a team of researchers, led by a professor at the State University of New York at Buffalo and including area high school students, has developed a novel method to search the vast archives of known gene sequences to identify and compare similar proteins across the many kingdoms of life. Using the comparisons to quantify the evolutionary closeness of different species, the researchers have identified Actinobacteria, a group of single membrane bacteria that include common soil and water life forms, as the base of the evolutionary tree.

At the ACA meeting, the researchers will present the results from the analysis of two different ribosomal protein families, called S19 and S13. Duax will present the analysis of protein S19, while high school student Alexander Merriman will present analysis of protein S13. Merriman joined Duax’s lab through a scientific mentorship program designed to give teenagers hands-on experience with cutting-edge research. “They are enthusiastic researchers and do great work,” Duax says of the students he welcomes into his lab each Friday.

Both analyses point to Actinobacteria as the last universal common ancestor. This agrees with previous work done by the group on proteins named S9 and S12. The researchers will continue to search for more evidence to add to their developing picture of the evolutionary tree. The group plans to analyze additional proteins, as well as DNA and RNA. “We are applying a systematic approach to make sense of a sometimes messy gene bank,” says Duax.

It may make sense, but it is way too soon to be sure that it is correct.

Photo: Actinobacteria/CDC, Libero Ajello

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4 Responses to Actinobacteria were last universal common ancestor (LUCA)?

  1. It may make sense, but it is way too soon to be sure that it is correct.

    They don’t need to be sure…they only need to promote propaganda and worry about whether it’s true or not, later.

    Remember “Ida” and “Archaeoraptor”?
    It’s all about rushing to judgement, getting a lot of media buzz promoting their myth, and then later quietly retracting the ‘fact’ when new evidence comes to light which contradicts it.

  2. press media (paper, radio, tv, internet) like to make big deal even against scientist wishes. need subscribers to survive i think, no?

    sergio

  3. Look on the bright side – if Actinobacteria is LUCA, that tells us precisely what needs to be explained by chemical evolution. Should be easy after that.

  4. I’m pretty sure Actinobacteria isn’t at the root of life. Protein signature sequences and 16S rRNA phylogenies seem to indicate that Firmicutes are at the base of the tree, and transition analyses suggest that the Chloroflexi phylum is at the base.

    Either way, it seems apparent that bacterial flagella were present in the LUCA, since Firmicutes are flagellated and Chloroflexi clearly encode flagellar genes.

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