It is thought that viruses played a central role in the early evolution, before the diversification of bacteria, archaea and eukaryotes, at the time of the last universal common ancestor of life on Earth.
Therefore, it is reasonable to presume that transfers of these elements occurred relatively recently, but certainly before the diversification of the ECC species.
This tree clearly demonstrates that the expansion of the E spl -complex occurrE spl -complexplit between Nematoccurredafterera and before the diversplitation of the Schizophora.
We conclude that OR and V1R arose in chordates after the cephalochordate-urochordate split, but before the diversification of jawed and jawless vertebrates.
However, even the PHYRN-NJ tree lacks resolution at some nodes, specifically for the events occurring after the emergence of Unknown 2 (archaea) and before the diversification of RAD51 groups (XRCC2, XRCC3, RAD51B-D).
The acquisition of a CBM1 may have occurred early before the diversification of the AA3_1 family in the Ascomycota division, or alternatively this modular organization may have been prematurely lost in Basidiomycota.
This acceleration of evolutionary rate would have occurred in the stem branches of the domains Bacteria and Archaea, namely after their separation but before the diversification of the lineages now present in these two domains.
There is good evidence from gene family and synteny analyses that two whole genome duplications (WGDs) occurred in the vertebrate lineage, after its divergence from tunicates and cephalochordates, but before the diversification of jawed vertebrates and possibly even before divergence of lampreys [ 6– 10].
Our conclusion, like Higgs, and like Crick before us, is that the diversification of amino acids in the genetic code is the primary motive force acting on genetic code evolution.
23 All three types of recombination events were analysed in this way, namely events before the common ancestors, during the diversification of clade A, and during the diversification of clade B (see online supplementary figure S2).
Additionally, the paranasal sinuses have been identified both as a site for the diversification of P. aeruginosa before spreading into the lower airways [ 7] and as a site of persistence in CF patients who underwent lung transplantation, whereupon these clones colonise the transplanted lungs that were primarily free from P. aeruginosa[ 8].
