2018, № 72UDC: 573; 575.01
Evolutionary and adaptation differences in the organization of species genome and their importance in the selection of plantsThe parameters of the structural and functional organization of species genomes are considered in terms of assessing species that are promising for breeding. The system of genomic characteristics of evolutionarily labile and evolutionarily conservative species developed by the author is the basis for selecting the source material for breeding. In the case of the evolutionary development of a taxon in the horizontal direction (cladogenesis or adaptive radiation), the traits of low specialization of the evolutionarily-labile species genomes at each speciation step in the course of progressive specialization are gradually replaced with alternative (evolutionarily conservative) traits, which reach their maximum expression in the terminal species: a reduction in the number of acrocentrics (Robertsonian fusion), polyploidization, an increase in the number of interspecific chromosome (inversion) rearrangements, the “dispersal” of heterochromatin and mobile elements over chromosomes, a sharp restriction of recombination, the formation of adaptive inversion polymorphism, and an increase in the areas of attachment of chromosomes to the nuclear envelope. The revealed parameters of the structural and functional organization of the genome in the species that are generators of speciation and in the inert (conservative) species in terms of speciation characterize the evolutionary heteropotential of species genomes and the nonequivalence of species with respect to natural selection. The former generate clusters of affiliate species, whereas the latter create their own species system of genetic adaptation (polymorphism) and usually terminate phyletic lines. Evolutionarily labile species have relatively small ranges and narrow ecological niches (i.e., are stenobiontic), whereas the evolutionarily conservative species have large ranges (i.e., are eurybiontic). In selection work, preference should be given to species (among closely related groups) that have the following parameters: a smaller number of chromosomes, a low level of recombination, a high intraspecific chromosomal polymorphism, heterochromatin chromosomes dispersed on chromosomes and mobile genetic elements, and presence of diffuse chromocenter.
Keywords: Evolution, selection, genomic reorganization, heterochromatin, genome architecture
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- Stegniy Vladimir Nikolaevich, DSc in Biology, Professor, Head of the Department of Cytology and Genetics, National Research Tomsk State University.