There is a further assumption that underlies the applicability of this analysis. We assume that in the case of the conserved gene sequences inclusive of introns and the coding segments, extensive restructuring through recombinations have not taken place. Indeed the first order formalism developed here implicitly assumes that all changes to a DNA sequence that have resulted in the form that we observe now have taken place through mutational changes only, and recombinations and transpositions have not had any major impact on the sequences.