A comparative-based phylogenetic study in the evolution of 16S rRNA and rad a genes in Archaea.

Archaea are ubiquitous in their presence and abundant not only in extreme environments, but also in soil, oceans and freshwater, where they may fulfil a key role in the biogeochemical cycles of the earth. The identification of archaeal genomic signatures elucidates us a measure of distinctiveness of Archaea as a coherent group, although these signatures can differ according to the degree of stringency. The 16S rRNA and the Rad A genes are highly conserved in living organisms and are very useful for the phylogenetic analysis. Phylogenetic trees are constructed using the molecular evolutionary genetics analysis (MEGA) tool by neighbour joining (NJ) method and repeated bootstrapping for 5000 times was performed. The two trees were then compared using the Compare2trees and statistically analysed using the MEGA tool. The two phylogenetic trees show a similarity of 54.9%. In both the trees, the taxon Thaumarchaeota shows a high level of variance. The species Cenarchaeum symbiosum A shows a high level of similarity with the sequences of higher organisms (Euryarcheota-eukaryota), which shows that it has branched away to higher organisms from a closely related Protozoa, Eubacteria ancestor.