EVOLUTION OF DARWINISM. The process that defines the essence of modern biology
Authors:   Institute of Molecular Biology and Genetics of the NAS of Ukraine, Kyiv, Vagyn Yu.V. 
Published: November 2024

It must be admitted that the victory of Darwinism in the dispute between the supporters of Lamarck and Darwin, which lasted more than 150 years, was ensured by Lamarckism, however paradoxical this statement sounds. This victory occupies a unique place in the history of biology, because it took place not against, but thanks to Lamarck’s supporters. It was the latter who paved the way for it, launching Lamarckism as an engine for the development of Darwinism. The development of Darwin’s idea of ​​natural selection as a leading factor in evolution has been supported in our time by data obtained at the molecular genetic level. In recent decades, many genetic mechanisms controlling the development of organisms have been deciphered. Studies of these mechanisms began with the most meritorious genetic object — the Drosophila fruit fly. It was on Drosophila that the fundamental principles of genetic control of ontogenesis were established. At the same time, the role of genes in establishing the axes of symmetry of the body was revealed. It was proved that cells determine their position in space by gradients of morphogens. Further studies have shown that many principles of genetic control of development, discovered in Drosophila, are valid for other animals as well. So, for example, Hox genes were found in all bilaterally symmetrical animals and even in jellyfish. Moreover, in all animals, they play a key role in the specification of various body parts. The remarkable lability of HOX protein functions over the course of evolution has been revealed, and this lability makes them the best system to date for understanding how the functions of transcription factors evolve in animals. Because HOX proteins function in many different cell types and at different stages of development, their functions may have been subject to selective pressure, allowing them to fit into almost all genetic patterns of development by changing morphology. We can say that research on developmental genetics, starting with drosophila, has today covered representatives of various animal species: butterflies and marine worms, sloths and manatees, snakes and birds, lancelets and ascidians and others. Interest in such unusual objects is connected with the fact that developmental genetics has become an integral part of evolutionary theory. All signs of any organism arise in the process of ontogenesis, and therefore, in one way or another, depend on developmental genes. These studies have shown that changes in the control of the expression of developmental genes are at the basis of the emergence and evolution of new forms. When Darwin, yielding to Lamarckism under the pressure of criticism, expressed the hope that future researchers would prove him right, he obviously had no idea that this evidence would be obtained at an extremely fundamental level. But it would be even more surprising for him to imagine that the results of research obtained at the specified level will become the basis of retrospective evidence of the correctness of his teachings up to the origin of life itself. Initially, Darwinism strongly relied on the doctrine of natural selection as the leading factor in evolution. It was the main theoretical postulate of Darwinism. However, in the sixth, last surviving edition of The Origin of Species, Darwin sacrificed natural selection in favor of Lamarckism for a number of reasons. This was followed by the degradation of Darwinism, which led to the fact that at the beginning of the 20th century most biologists, although they accepted the very concept of evolution, but few of them believed that natural selection was its main driving force. As such, Lamarck’s “certain” variability, Hugo de Fries’s orthogenesis and species mutations prevailed. However, in 1926, the unification of Darwinism and genetics began, from which the synthetic theory of evolution grew. Within the framework of this theory, natural selection regained its role as the leading factor in biological evolution. As a result, within the framework of a new evolutionary synthesis, the mechanism of morphological evolution was revealed, covering the process of speciation: the action of natural selection at the level of phenotypes, aimed at transforming the hereditary program of ontogenesis, as a response to a long-term and unidirectional change in environmental requirements. Thus, it was established that compared to the solution proposed on the basis of the results of research on the synthetic theory of evolution, nature itself found a “more sophisticated solution” for the formation of a diversity of forms of organisms, creating a genetic code of morphological evolution. At the end of the consideration of the evolution of Darwinism, the process that began with the publication of Darwin’s seminal scientific work “The Origin of Species”, we present the main milestones of the specified process: at the turn of the 19th and 20th centuries, Mendel’s laws were rediscovered, which led to the formation of modern genetics; the union of Darwinism and genetics, which started 90 years ago, is the synthetic theory of evolution; the established distinction between the evolutionary roles of structural genes and developmental genes, which was a consequence of a new evolutionary synthesis. It was they who significantly influenced the development of Darwinism, which, until now, determines the way of formation and the essence of modern biology. The author wrote the proposed monograph, first and foremost, for himself. However, he also sought to convince the reader that the publication of “The Origin of Species” marked the beginning of modern biology, as well as that Darwinism, the quintessence of which is the evolution of organisms by natural selection, will now and will continue to have a decisive influence on its further development. In favor of this thesis, we can quote the statement of Sir Peter Medawar, winner of the Nobel Prize in Physiology or Medicine in 1960, who emphasized that “the alternative to the evolutionary way of thinking is the absence of any thinking”. So, the facts presented in the monograph made it possible to prove the correctness of the central position of Darwinism about the leading role of natural selection in biological evolution.