{c}

<George E. Fox> is a researcher in <ribosome> function, <ribosomal RNA> structure and molecular <evolution>. The University of Houston identifies him as a co-discoverer of <Archaea> and describes his laboratory's use of comparative analysis to investigate <ribosomal RNA> organization and the evolution of the <ribosome>.<George E. Fox faculty profile at the University of Houston>[Research Interests, comparative RNA analysis and discovery of Archaea]{ref}

In 1977 Fox was first author of a study characterizing <16S ribosomal RNA> from ten methane-producing microbial species. Digestion with <ribonuclease T1> generated short fragments for <ribosomal RNA oligonucleotide cataloguing>. Comparing the catalogs revealed a distinct evolutionary group, distant from typical <bacteria>.<Classification of methanogenic bacteria by 16S ribosomal RNA characterization by George E. Fox and others>[Abstract, ten species and RNase digestion]{ref} Fox and <Carl R. Woese> then jointly published the broader proposal distinguishing three primary lines of descent.<Phylogenetic structure of the prokaryotic domain: the primary kingdoms by Carl R. Woese and George E. Fox>[Abstract, ribosomal RNA sequence characterization and primary groups]{ref}

The catalog comparison used an association coefficient
$$
S_{AB}=\frac{2N_{AB}}{N_A+N_B},
$$
where $N_A$ and $N_B$ count <nucleotide> residues represented by catalogued fragments of at least six nucleotides, and $N_{AB}$ counts the residues in their shared sequences. The weighting is by represented residues, rather than merely by the number of different fragment strings.<Classification of methanogenic bacteria by 16S ribosomal RNA characterization by George E. Fox and others>[Page 4537, definition of the binary association coefficient]{ref}

For a constructed pair with $N_A=100$, $N_B=140$ and $N_{AB}=60$, the coefficient is $120/240=0.5$. Identical catalogs would give one, and no overlap would give zero. This arithmetic explains the comparison's normalization; the value is not directly a fraction of whole-genome identity or a calibrated divergence time.

Fox's work helped make evolutionary relationships among superficially similar <microorganisms> experimentally accessible through a shared molecular system, the <ribosome>.

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{title=George E. Fox}
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 George E. Fox (source code)