It is anticipated that more than 10 functionally distinct GTs are required to build the AGP glycans, and so far fucosyltransferases (AtFUT4, AtFUT6) [ 15], galactosyltransferases (AtGALT2 [ 16] and AtGALT31A [ 17]), and a glucuronosyltransferase (AtGLCAT14A) [ 18] have been characterized.
Within the land plants, it is apparent that both NRT1s and PTRs are polyphyletic, i.e. functionally characterized NRT1s and PTRs are more closely related to functionally distinct proteins than to other proteins with identical function.
The hypothesized mechanism explaining this pattern is that distantly related taxa are more likely to be functionally distinct or have lower niche overlap than closely related taxa [18], [19], [20].
Taken together, these results suggest that P. aeruginosa DinB contributes to H2O2-induced mutagenesis by one or more mechanisms that are functionally distinct from that involving its ability to catalyze error-prone bypass of 8-oxo-dG (see Discussion).
More recently, phenotypic and functionally distinct subpopulations of cTfh cells have been described, according to the differential expression of the chemoquine receptors CXCR3 and CCR6 on CD4 + CXCR5+ T cells [ 17].
With the availability of whole genome sequences, many more of these structurally and functionally distinct non-coding RNAs were discovered both experimentally and by bioinformatic prediction (Ambros and Lee, 2004; Ambros et al., 2003; Kozomara and Griffiths-Jones, 2011).
Unfortunately, there is not a consensus as to the exact boundaries of perirhinal cortex in the human and whether the more anterior temporal polar region should be considered a functionally distinct region from the more posterior portion of perirhinal cortex.
In particular, RNA editing is an important post-transcriptional event in gene modification that alters one or more translation codons, thereby giving rise to functionally distinct proteins from a single gene [23].
More recent investigations revealed thatVps34 constitutes several functionally distinct complexes.
Genome-wide gene expression studies and analyses of physical interactions between proteins and mutant phenotypes have led to the identification of 164 functionally distinct modules containing two or more proteins and 93 modules containing only one protein [5].
