Soviet Lysenkoism was an unfortunate chapter in the biology of the 20th century. In connection with this subject, mention should be made of the aspect of jump transitions between two or more species. Lysenkians assumed that an organism is capable of reacting to some external stimuli in that it switches the ontogenetic system in such a way that, in a single jump, the progeny acquire the character of the members of a different biological species. Descriptions of observations in which poorly fertilized wheat suddenly began to form rye caryopses in its spikes or poorly fertilized rye began to form couch grass caryopses now sound like a students’ rag or April-fools joke.
Lysenkists completely discredited their learning, not only in that they physically liquidated their opponents in the interests of rapid dissemination of their ideas, or rather in the interests of fulfilling their ambitions of power, but also in that they extensively falsified their experimental data. Consequently, the results that were accumulated at the time of Lysenkoism are mostly worthless. The very idea of the transition of one species into another through switching of alternative ontogenetic programs cannot, however, be automatically rejected. However, contemporary knowledge related to the course and mechanisms of biological evolution exclude the possibility that such a phenomenon could have any importance in the evolution of organisms.
It is true that all organisms with sexual dimorphism and organisms whose life cycle includes a larval phase are capable of maintaining genes for two or more different, mutually exclusive ontogenetic programs in their genome. However, in these cases, natural selection constantly controls the functioning of the individual ontogenetic programs and greatly “penalizes” individuals that have a program damaged by mutations. However, if the population were to employ only a single program for a long time, it is probable that the genes for an alternative program would be gradually inactivated as a consequence of the accumulation of mutations. See also Frozen plasticity theory.