A plasmid digene construction designed before [Tchuraev, R.N. (1982) J. Gen. Biol. 43, 79–87] has been realised, including feedback by repressing proteins with given trigger regime of gene functioning. Experimental tests of the expected epigene properties of the obtained pECPI recombinant plasmid involving lacI and cI857 regulatory genes have shown a phenomenon of steady inheritance of two alternative epigenotypes lacI1cI0 and lacI0cI1 , as well as an external toggle switch through metabolitic and temperature signals from one inherited functional state of the cyclic digene system into another. Thus, we have constructed a hereditary unit of a specific kind, namely, a two-component stationary epigene with preset properties.
