Vol 85, No 6 (2024)

Since the time of Charles Darwin, the study of the mechanisms of domestication of animals as a model of rapid evolutionary transformations has been of general biological importance. Methods of Geometric morphometrics (GM) make it possible to assess the morphogenetic changes that occur during domestication. Using the experimental strains of American mink Neogale vison, selected for aggressive and tame behavior, significant differences in the centroid size (CS) and shape of the mandible were established between them. Cage non-selected and wild Canadian minks were used as controls. Selection has led to an increase in the CS of mandibles in aggressive and their decrease in tame ones. The greatest differences in the shape of mandibles were manifested between the aggressive and tame strains. The destabilization of mandible development, indirectly estimated by the volume of within-group morphospace (Vm) along the first canonical axes, turned out to be most pronounced in males and females of the tame mink strain, which is directly consistent with the theory of destabilizing selection by D. K. Belyaev. After 16–17 generations of mink selection for aggressive and tame behavior, morphogenetic effects were found, expressed in the divergence of the shape of their mandible, accompanied by destabilization of development, and reflecting the high rate of experimental domestication. The differentiation of the aggressive and tame minks by the shape of the mandibles exceeds the level of sexual differences and is comparable to the degree of morphological divergence between caged and wild Canadian individuals. It is accompanied by morphological hiatus and is formally close to the subspecific rank of intraspecific morphological differences compared with the morphological divergence of the American mink from another species – the Siberian weasel Mustela sibirica. The morphogenetic effects of American mink selection by behavior demonstrate the high adaptive and evolutionary potentials of this invasive species.

Based on the concept of bet-hedging, this study explores the mechanisms that maintain the Heracleum mantegazzianum Sommier & Levier populations size and age structure in the absence of a long-term soil seed bank for this species. The research focuses on the dynamics of mericarpia (“seeds”) in the soil bank of H. mantegazzianum, the number of seedlings, and juvenile individuals in the Middle Taiga subzone of the Komi Republic. The populations of H. mantegazzianum are characterized by the accumulation of a significant number of empty seed coats in the soil, while the median number of viable mericarpia does not exceed 2000 pieces per square meter. A prolonged period of natural stratification, lasting up to six months, guarantees that virtually all the seeds from the previous harvest will mature and sprout promptly in the spring. Consequently, in the European Northeast Russia climate, the plants H. mantegazzianum establish a transient seed bank. The number of juvenile individuals of H. mantegazzianum remains relatively stable at approximately 200 individuals per square meter, attributed to a consistent supply of new seeds, rapid spring development of seedlings, and the retention of individuals in a juvenile stage during their second year of life. The utilization of light resources during spring and autumn, along with the ability to enter a state of dormancy during the summer, contribute to the survival and maintenance of juvenile individuals under conditions of intense intra-specific competition. In H. mantegazzianum, the bet-hedging strategy is implemented through the reproduction of an extremely small fraction (less than 0.01%) of the total population, the presence of a sufficient bank of underground dormant buds, and the ability of juvenile individuals to enter a state of forced dormancy.

Molecular phylogeny has gained a crucial role for plant taxonomy in recent years. In some cases sequence comparison of the chloroplasts or nuclear genes and even whole genomes led to novel and unexpected results in taxonomic positions. For example, after publication of phylogenetic data a genus Minuartia s. l. was considered to be a paraphyletic group and subjected to taxonomic revision according to cladistics concepts. As a result, several new genera were identified and some genera were restored including Cherleria L., which includes 19 species. The genus Cherleria is of particular interest due to significant habitual differences in its representatives. Thus, to clarify the relationships between intergeneric taxa a search for new taxonomically significant traits is needed. For these purposes, the biomorphological characteristics of representatives of six model species of Cherleria were studied. In the article the most significant biomorphological characteristics such as the model of shoot formation, the morphology of the cushion, the nature of shoot branching, the presence or absence of specialized vegetative shoots for capturing space, the growth strategy and the structure of the monocarpic shoot are proposed to aid for identification of taxonomic position. Analysis of the biomorphological features of the studied species identified four growth strategies: a) the strategy of centrifugal growth; b) the strategy of centrifugal growth with the rare appearance of radially directed lateral specialized shoots of the semi-rosette type; c) the strategy of vector growth by active branching at the early stages of development, with subsequent “fading” in formation of lateral axes; d) the strategy of vector growth with the help of semi-rosette plagiotropic shoots with the subsequent filling of the internal space of the cushion due to orthotropic rosette shoots. Comparison of molecular phylogeny and biomorphology data allows us to identify biomorphological apomorphies: monopodial plagiotropic-semi-rosette–orthotropic-rosette model of shoot formation with specialized semi-rosette shoots for capturing territory, the presence of dicyclic monocarpic shoots, as well as plesiomorphies: monopodial rosette model of shoot formation, formation of a densely filled cushion, monocyclic, simply arranged monocarpic shoots. Based on these data, we put forward an assumption that for the genus Cherleria the initial model of shoot formation was the monopodial rosette model.