ABSTRACT
The suppressing effect on melanogenesis of genes determining high wool productivity in domestic sheep has been discussed for the first time. Morpho-physiological mechanism of suppression of the activity of pigment cells function in lambs of Tajik breed was shown: melanocytes lose their activity during some weeks-months after birth and migrate from the zone of usual localization on follicle papilla into forming hair. The result of genes-modificators' action (the period of postembryonic development, when white wool starts growing) is determined by their interaction with alleles of genes A and E: the lower intensity of melanogenesis, the earlier and more effective the inhibitory effect of genes-modificators. Some factors which suppress pigmentation are characterized: these are an increase in SH groups content, deficiency of tyrosine, rise in growth rate and reduction of the diameter of hairs, intensification of antagonism between melanocytes and keratinocytes. The problem is also interesting in evolutional aspect: since suppression of melanogenesis in the process of creating wooly sheep illustrates possible mechanisms of inhibition of one function, because of hyperfunction of other, such negative correlations could play significant role in evolution of organisms.
