Evolutionary Patterns in the Sequence and Structure of Transfer RNA: Early Origins of Archaea and Viruses
Figure 2
Timeline of organismal diversification.
Constraints representing non-competing hypotheses of organismal relationship (white circles) are used to define a timeline for the appearance of lineages in a universal tree derived from the sequence and structure of tRNA. Blue circles represent constraints representing competing hypotheses. They illustrate both the most parsimonious lineage relationship and their coalescence. Areas colored in light green, salmon, and light yellow are delimited by lineage coalescence and describe three evolutionary epochs. The timeline is given in a scale of additional steps (S) needed to fulfill constraints. S values were not normalized.