Two contradicting properties have been associated to evolutionary conserved alternative exons: higher sequence conservation and higher rate of non-synonymous substitutions, relative to constitutive exons.
According to the ENC index, lower values than the reference set indicate stronger codon usage bias which is associated to slower evolutionary rates while higher values indicate weaker codon usage bias and selection intensity.
In fact, when several LEE genes from strain RDEC-1 were compared to those from other AEEC, the variation appeared to be associated with evolutionary lineage and not host specificity [ 77].
However, as Antonovics noted four decades ago [6], we should expect most ecological changes to be associated with evolutionary change.
That may well be why both of those jumps seem to be associated with subsequent evolutionary leaps the advent of complex cells, in the first place, and of large animals, in the second.
Combined analyses of all genes confirmed increased selection to be associated with this evolutionary shift, but also for the evolution of parasitism in general.
As a result we identified both the gain and loss of a developmental dimorphism to be associated with rapid evolutionary diversification.
A number of genomic variables, such as expression level [ 16, 25, 50- 52], functional dispensability [ 25, 53] and pleiotropic effect [ 54, 55], are proposed to be associated with protein evolutionary rate.
We predict that such events will often be associated with fundamental evolutionary changes to gene regulation, gene repertoire and morphological diversity.
These genes are likely to be associated with co-evolutionary arms races between pathogenic microorganisms and hosts.
