It is now clear that histone variants have diversified in many species to assume crucial roles in transcriptional activation, DNA repair, chromosome segregation and other processes.
Core histones clearly differ in their evolutionary propensity to diversify as distinct variants.
These genes may be evolving under weak selective constraint but could also be selected for multiple variants (diversifying or balancing selection).
Because the Sydney 2012 variant has rapidly diversified within the population, as shown in recent studies [ 34], an immunological study of NoV variants is needed to examine the range of the outbreak.
During colonization, clones coexisted and diversified rather than a single variant dominating.
Isoforms occupy the same position within the heterooligomer and may be products of distinct genes or variants of a single gene diversified by alternative splicing or other mechanisms.
In addition to a desaturase activity, a number of FAD2 variants are known to possess diversified functionalities, catalyzing hydroxylations, epoxidations, or the formation of acetylenic and conjugated double bonds [ 35, 41, 42].
This platform is further diversified by replacement of canonical histones with histone variants and the chemical modification of both histone and DNA components of the nucleosome.
Accumulation of knowledge on such variants will allow us to distinguish conserved and diversified SD pathways among vertebrates and lead us into a deeper understanding of the vertebrate SD cascade.
Variants of the FAD2 enzyme are also known to have diversified functionalities in fatty acid modification, catalysing hydroxylation [ 13, 14], epoxidation [ 15], and the formation of acetylenic bonds [ 15, 16] and conjugated double bonds [ 17- 20].
