A missing paradigm: deciphering endocrine innovations among diverging regulations of alleles, paralogous and orthologous genes.

In endocrinology, there are many similarities in the regulation of gene expression between alleles, paralogous or orthologous genes, at the genetic or epigenetic level. However, there are also major differences in the spatial and temporal expression patterns of these genes, in particular between species. In few cases, it has been shown in vitro and/or in vivo that regulatory differences are mainly due to subtle differences (from one bp to less than 12bp) in the nucleotide sequence of transcription factor binding sites localized in the vicinity of the proximal promoter. In this short review, we propose to cite some of them, without claiming to be exhaustive. We also briefly review new methodologies that allow for more global studies of comparisons of expression regulations at the transcriptional level. We also discuss whether such studies could have given rise to any paradigm.