 
        
        	The Tree of Life representing the connections among all organisms has 
become
an icon of evolutionary biology. But recent analyses of completely 
sequenced
genomes and the discovery that horizontal gene transfer (HGT) has
significantly shaped microbial evolution have challenged the concept of 
the
Tree of Life. We have determined the general outline of the tree using
complete genome data from representative prokaryotes and eukaryotes and
using a new genome analysis method that makes it possible to 
reconstruct
ancient genome fusions and phylogenetic trees even in the presence of 
HGT.
Our analyses indicate that the eukaryotic genome resulted from a fusion 
of
two diverse prokaryotic genomes, and therefore at the deepest levels 
linking
prokaryotes and eukaryotes, the tree of life is actually a ring of 
life. One
fusion partner branches from deep within an ancient photosynthetic 
group,
and the other is related to the archaeal prokaryotes. The eubacterial
organism is either a proteobacterium, or a member of a larger 
photosynthetic
group that includes the Cyanobacteria and the Proteobacteria.
            
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 Getting Under Europa’s Skin
                    
                    Getting Under Europa’s Skin Tracing Formation and Evolution of Outer Solar System Bodies Through Stable Isotopes and Noble Gas Abundances
                    
                    Tracing Formation and Evolution of Outer Solar System Bodies Through Stable Isotopes and Noble Gas Abundances Photosynthesis, a Planetary Revolution
                    
                    Photosynthesis, a Planetary Revolution Xenon: King of the Gases
                    
                    Xenon: King of the Gases