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Cultures of the methane-producing archaea Methanosarcina, have recently been isolated from Alaskan
sediments. It has been proposed that methanogens are strong candidates for exobiological life in extreme
conditions. The spatial environmental gradients, such as those associated with the polygons on Mars' surface,
could have been produced by past methanogenesis activity. The 16S rRNA gene has been used routinely to
classify phenotypes. Using the fractal dimension of nucleotide fluctuation, a comparative study of the 16S
rRNA nucleotide fluctuation in Methanosarcina acetivorans C2A, Deinococcus radiodurans, and E. coli was
conducted. The results suggest that Methanosarcina acetivorans has the lowest fractal dimension, consistent
with its ancestral position in evolution. Variation in fluctuation complexity was also detected in the transcription
factors. The transcription factor B (TFB) was found to have a higher fractal dimension as compared to
transcription factor E (TFE), consistent with the fact that a single TFB in Methanosarcina acetivorans can code
three different TATA box proteins. The average nucleotide pair-wise free energy of the DNA repair genes was
found to be highest for Methanosarcina acetivorans, suggesting a relatively weak bonding, which is consistent
with its low prevalence in pathology. Multitasking capacity comparison of type-I and type-II topoisomerases
has been shown to correlate with fractal dimension using the methicillin-resistant strain MRSA 252. The
analysis suggests that gene adaptation in a changing chemical environment can be measured in terms of
bioinformatics. Given that the radiation resistant Deinococcus radiodurans is a strong candidate for an extraterrestrial
origin and that the cold temperature Psychrobacter cryohalolentis K5 can function in Siberian
permafrost, the fractal dimension comparison in this study suggests that a chemical resistant methanogen could
exist in extremely cold conditions (such as that which existed on early Mars) where demands on gene activity are
low. In addition, the comparative study of the Methanococcoides burtonii cold shock domain sequence has
provided further support for the correlation between multitasking capacity and fractal dimension.
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