Genetically based stable colour polymorphisms provide a unique opportunity to study the evolutionary processes that preserve genetic variability in the wild. Different mechanisms are proposed to promote the stability of polymorphisms, but only few empirical examples have been documented, resulting in an incomplete understanding of these mechanisms. A remarkable genetically determined stable col...

The genotypes of three color mutants in goldfish: a depigmentation character of larval melanophores, albinism and a recessive-transparent character, were analyzed by crossing experiments. The depigmentation character in the common goldfish is controlled by two dominant multiple genes, Dp1 and Dp2, and only fish with double recessive alleles dp1dp1 dp2dp2 can retain larval melanophores throughou...

Pigment pattern variation across species or populations offers a tractable framework in which to investigate the evolution of development. Juvenile threespine sticklebacks (Gasterosteus aculeatus) from marine and freshwater environments exhibit divergent pigment patterns that are associated with ecological differences. Juvenile marine sticklebacks have a silvery appearance, whereas sticklebacks...

The melanotrope cells of the amphibian pars intermedia secrete the peptide melanophore stimulating hormone (aMSH), which induces pigment dispersion in dermal melanophores. The purpose of the present study was to determine: (1) whether prolonged activation of the secretory activity of the pars intermedia is associated with hypertrophy, hyperplasia or both and (2) whether the melanotrope cells fu...

Intermediate filament (IF) dynamics during organelle transport and their role in organelle movement were studied using Xenopus laevis melanophores. In these cells, pigment granules (melanosomes) move along microtubules and microfilaments, toward and away from the cell periphery in response to alpha-melanocyte stimulating hormone (alpha-MSH) and melatonin, respectively. In this study we show tha...

The reaction-diffusion system is one of the most studied nonlinear mechanisms that generate spatially periodic structures autonomous. On the basis of many mathematical studies using computer simulations, it is assumed that animal skin patterns are the most typical examples of the Turing pattern (stationary periodic pattern produced by the reaction-diffusion system). However, the mechanism under...

α-MSH and light exert a dispersing effect on pigment granules of Xenopus laevis melanophores; however, the intracellular signaling pathways are different. Melatonin, a hormone that functions as an internal signal of darkness for the organism, has opposite effects, aggregating the melanin granules. Because light functions as an important synchronizing signal for circadian rhythms, we further inv...

The microtubule motors, cytoplasmic dynein and kinesin II, drive pigmented organelles in opposite directions in Xenopus melanophores, but the mechanism by which these or other motors are regulated to control the direction of organelle transport has not been previously elucidated. We find that cytoplasmic dynein, dynactin, and kinesin II remain on pigment granules during aggregation and dispersi...