To produce the evolutionary constraint profile, the rates were then converted to relative constraint by normalizing to a range between 0 and 1, inverted by subtracting from 1 (because a region of low evolutionary rate is under high evolutionary constraint), and plotted against the position in the protein.
Although insl5b and insl3 are the teleost genes under the weakest evolutionary constraint (a result also supported by the molecular clock analyses), they are under stronger purifying selection than mammalian RLN and INSL6, which have dn/ds ratios of 0.64 and 0.46 respectively, with the B-chain of mammalian INSL6 exhibiting the highest rate of dn/ds at 0.78.
Stochastically, only the robustness of the results is increased, if the complete elongated sequence evolved under the same evolutionary constraints [ 5].
However, several features set the FBX superfamily apart from these other pseudogene-rich families, suggesting that the FBX superfamily is not under the same evolutionary constraints.
Proteins that are under the same evolutionary constraints are likely to demonstrate the same pattern of selection across individual codon sites even if the primary sequences have evolved to a point where the sensitivity of the homology methods is insufficient to predict orthology.
They are under the strong evolutionary constraints and must have played important roles in the vertebrate evolution.
PTLV-4 LTR sequences from all six animals, which are typically one of the most divergent regions in PTLV since it is a non-coding region and is not under the same evolutionary constraints as coding regions, shared 98.4%99.5%% nucleotide identity with the HTLV-4 LTR.
In particular, Yi et al. (2012) stress that the IR is under stronger evolutionary constraint than the large single copy (LSC) or small single copy (SSC) as shown by the distribution of repeated elements and indels and the base substitution patterns.
Although developmental enhancers, as a whole, are under strong evolutionary constraint, the selective pressure imposed on enhancers varies greatly phastCons, a conservation score, ranges from 0 (indicating no conservation) to 1 (perfect conservation) (Blow et al. 2010; Clarke et al. 2012).
These findings support the idea of the developmental hourglass model (Domazet-Lošo and Tautz, 2010; Kalinka et al., 2010) while suggesting that substantial neutral divergence of molecular phenotype (gene expression) can accumulate in the form of cis-regulatory variation even under strong evolutionary constraint at the organismal (embryonic) level.
