In highly conserved widely distributed ortholog groups, the main evolutionary force is assumed to be purifying selection that enforces sequence conservation, with most divergence occurring by accumulation of neutral substitutions.
Within such an ortholog group, the general expectation is that the main evolutionary force is purifying selection, which is reflected as sequence conservation, with most divergence between the orthologs arising from neutral substitutions.
In this model, the groups G1 to G3 defined by MDS correspond to three main evolutionary pathways from the ancestors of PEP receptors.
AB and OV are representatives of two main evolutionary cichlid lineages (tribes) from East Africa, the modern haplochromines and the more basal group of the ectodines, respectively (see, e.g., Salzburger et al. 2002, 2005).
Massive intron losses were inferred for several groups, especially yeasts, nematodes and insects, whereas in vertebrates and plants intron gain was inferred to be the main evolutionary trend [ 45].
Sexual selection is one of the main evolutionary forces that drive signal evolution.
Dr Ed Morrison, a senior lecturer in evolutionary psychology at Portsmouth University, says the main evolutionary theory for mate selection is "optimal outbreeding" – that "the best mate is one who is similar to you, but not too similar".
The main evolutionary challenge was to hover with stability near flowers so as to probe the flower's petals and gain the nectar reward.
Two main evolutionary lineages are present within the "best" MP tree (Fig. 6) and the ML tree (Fig. 7), hereafter referred to as group I and II.
These genes are unambiguously categorized into two distinct evolutionary groups.
