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Mon Mar 17 09:16:27 CDT 2008
NASA's primary goal is to study nature of evolution as it happens throughout the Universe.
What aspects of evolution on Earth are the most ussedful to this goal?
In that microorganism are considered in many ways basal to the evolution of life here on Earth,
NASA's goal should be focused in large measure on the evolutioin of microbial life, particularly on
the evolution of microbes as communities (not as individual organisms, which is an anthropomorphic
distillate of the problem.
Besides very little is now know about the dynamics of evolution in the microbial world; but it is
known that microbial evolution is far more drived by a dynamic in which horizontal gene flow is
essential.
New directions in characterizing microbes, e.g., the advances in ther study of biofilms, the study of
cell-cell contacts and gene flow resulting therefrom; the role of viral vectors in genetic communication
in microbial communities; the incredible physical networking that seems part and parcel of microbial
communities -- all argue for a primary focus by NASA on evolution in the microbial world.
Microbial evolution operates according to a significantly different evolutionary dynamic than does
evolution in the world of multicellular eukaryotes (and probably eukaryotes in general).
Besides, it is an evolutionary dynamic based primarily on HGT (and other forms of cell-cell exchange,
innovation sharing) that may well drive evolution at the earliest stages of cellular evolution – before
what we call the “Darwinian transition” and other major saltational occurrences that seem to occur
through the evolutionary course. It is this type of dynamic that would seem to be most pertinent to
developing NASAs concept of evolution throughout the Universe.
And it is in this venue that the work in the Pace lab on the electron tomography of bacterial cells and
their communal responses and Pace’s broader work on determining the extent and parameters of
microbial diversity in general that dovetails so well with NASA’s goal of exploring evolution in the
context of the Universe as a whole.