If the cost is similar for the two species, proboscis length does not diverge, individual moths do not specialise on flowers with one corolla-tube depth, there is no selective fertilizing within plants and there is no evolutionary pressure for divergence in corolla-tube depth.
But although changes in isolated genes underlying differences between ecologically divergent sister species have been linked to changes in the environment (Cobbett and Goldsbrough 2002), evolutionary pressures acting on the genome as a whole and the specific role of environmental pressures on divergence have been challenging to study.
As a measure of this divergence, pressure ranges were calculated between the minimum pressure in the time period 15 150 s and the mean pressure in the time period 180 600 s for each limb.
Moreover, a novel computational framework is developed for the evaluation of bubble point pressure to prevent divergence of the solution when the reservoir conditions change.
However, a relatively similar study (Rand and Kann 1996) on one of the mitochondrial genes gave a different point of view, which suggested that some pressure of adaptive divergence might be acting in conflict with forces removing or rather eliminating variation.
However, alignments suggest that genes in this subfamily have evolved under some pressure for ZNF divergence (supplementary table S3, Supplementary Material online, and discussed later).
The most likely selection pressure for the divergence of individual VSGs in different strains is to favour superinfection of a host by a second trypanosome strain.
There was significant enrichment for SNP locations in non-coding or synonymous amino acid sites, indicating significant selective pressure since the divergence.
The high proportion of nonsynonymous mutations observed at CCR5 first suggested the occurrence of selective pressure for aminoacid divergence targeting this gene (Carrington et al. 1997).
Furthermore, these properties were studied as a function of the single parameter of the model: a cutoff that measures selection pressure against structural divergence.
