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Abstract

Genes define the structure and function of the body and brain. Genetic alterations result sometimes in unexpected changes, for example albinism is not only a modification of the coat color but has also an effect on neuronal wiring. Several species are bred specifically for coat colors, such as the American mink. Therefore we were interested, if color mutations in the mink have an effect on the organization of the olfactory bulb, an evolutionary old structure. We investigated adult males of different coat color varieties of the American mink: “standard” (Neovison vison var. atratus), “silverblue” (Neovison vison var. glaucus), “pastel” (Neovison vison var. suffuscus), “wild” (Neovison vison var. carinum) for the absolute volumes of the olfactory bulb layers using a morphometric system. The results reveal significant differences among the color varieties, especially Neovison vison var. glaucus (g) shows differences compared to either Neovison vison var. suffuscus (s) or Neovison vison var. atratus (a) or both, in absolute volume of the glomerular layer (g: 18.1 mm3; s: 23.0 mm3; a: 21.7 mm3), the external plexiform layer (g: 29.4 mm3; s: 35.8 mm3), the mitral cell layer (g: 4.4 mm3; a: 7.2 mm3) and the stratum album (g: 11.8 mm3; s: 16.3 mm3), whereas there was no significant difference in any of the layers compared to Neovison vison var. carinum. Neovison vison var. glaucus is characterized by the modification of the recessive gene (pp), with the genetic modification affecting the myosin- and actin-binding domains – also responsible for intracellular vesicle transport – an important process for neuronal wiring. Thus, our results stronlgy indicate that the genes responsible for pigmentation also define the neuronal structure.