Morphogenetic Effects of Long-Term Selection of American Mink (Neogale vison Schreber, 1777) Strains on Characters of Defensive Behavior: Intra- and Interspecific Aspects

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 nonselected 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 minks. 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 the 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.