Genetic comparisons of eumelanosome ultrastructure

We recently reported the existence of several new ultrastructural components of the eumelanosome matrix from developing chick pigment epithelium. The material used in the original study was obtained from a random sample of heterogeneous chicken. We have now extended this analysis to four genetically well-characterized chicken types: jungle fowl, blue, dominant white, and recessive wheaten. In these four genotypes there are specific ultrastructural alterations in the eumelanosome matrix. These alterations are different for each of the genotypes studied and are probably reflective of differences in the functional nature of the genes involved. The data thus provide evidence as to which genes are structural and which regulatory in action. Furthermore, since the material analyzed was all derived from pigmented pigment epithelium, it is clear that these melanosomes are affected by genes previously thought to leave them untouched. Finally, data are presented that these new ultrastructural elements are also found in a different class of animals, the C57BL/10 mouse.