The corresponding genes are under strong purifying selection, a selective regime that eliminates virtually all newly-occurring amino-acid substitutions.
The Ornstein-Uhlenbeck models were fitted using either a single selective regime (one single σ, selection strength α and optimum parameter θ) or multi-regime processes.
And finally, there was a concern raised about whether the evolved population was oscillating or was being entrained by the selective regime imposed (FACS-based selection at 10 and 14 hour intervals).
To model positive selection at the locus, we used an additive selective regime in which relative genotypic fitnesses were w (BB ) = 1, w (Bb ) = 1 − h s, and w (bb ) = 1 − s.
The parameter α describes the strength of selection, the higher the value of α, the stronger the selective regime; θ is the value of the selective optimum [ 31].
Clade model analyses revealed that, after duplication, the selective regime experienced by many alignment sites changed from weak purifying selection to either neutral evolution or weak positive selection.
Zero generations removed from the selective regime is the case in which the dams were taken from selected lines.
The signature left by balancing selection should be detected by the Ewens-Watterson homozygosity test, since this selective regime should lead to an excess of heterozygotes, as has been shown for the Human Leukocyte Antigen (HLA) loci [ 61].
Here, we show a similar pattern at the interspecific level, and describe how an intricate selective regime can shape diversification of a complex behaviour across species.
Reduced bacterial and archaeal diversity might reflect the selective regime imposed by the contamination of this site.
These changes of selective regime might have played a role in the evolution of neuroendocrine functions controlling feeding and reproduction in mammals.
