The relatively specific phenotype in the exocrine pancreas and skin pigmentation might be related to the specific requirement of different tissues, timing of expression and molecular context.
In contrast to the presence of COOH-tail phosphorylation of R-Smads in almost all cell types and tissues, timing, duration, extent and functional implications of linker phosphorylation depend on cell type and context.
Moreover, xenotransplantation was presented as a potentially superior therapy with numerous advantages over allotransplantation including 'virtually unlimited' supply of tissue, flexible timing of transplant procedure, and limited or no requirement for immunosuppression (National Health Medical Research Council NHMRC 2009b, 20 21).
It is known that the net effect of VEGF-A can vary depending on the target tissue, the timing and the concentration [35].
Given the problems of examining adolescent breast tissue, the timing of the full development of the breast gland is not well understood, but full maturation of the breast takes several years after menarche [ 21].
Importantly, as well as activating mechanisms that preserve genome integrity and protect dormant origins in this tissue, the timing and expression of regulators such as p21 and p16 must be appropriately controlled.
Another advantage of the ASE approach is to detect candidate genes for further evaluation as the only requirement is, given the proper tissue and timing, that the transcripts be differentially expressed between groups of interest (e.g., uninfected and MDV-infected birds), which is not limited by the effect size.
On the other hand, the OsWRKY CORs would indicate the existence of WRKY protein complexes where WRKYs belonging to different subgroups bind to different cis-regulatory elements, thus giving them different targets that are expressed under the same conditions, tissue and timing.
It has been proposed that duplicate gene copies may 1) accumulate nonsense mutations in regulatory or gene elements and become non-functionalized, 2) diverge in the tissue or timing of expression compared to the ancestral copy and become sub-functionalized, or 3) acquire new functions and be neo-functionalized [ 30].
Because the same somatic insertions were found in different tissues, the timing of many events could be estimated as early in development, before the differentiation of tissues, including the germ line.
