[Aspects of the problem of regulator genes in the genetics of development].

The concept of gene-regulator in the genetics of prokaryotes and eukaryotes is considered. On the basis of numerous data, a conclusion is drawn on the presence of gene-controlled substances in eukaryotes which activate and suppress cell differentiation at many levels from transcription to posttranslation. It is proposed to define the gene-regulator in eukaryotes as a gene controlling the phenotypic expression (rather than activity only) of other genes at different levels of regulation.