In the first decade of the 20th century two reports appeared in the literature, which supported the notion that eye colour was inherited as a simple Mendelian trait.11, 12 Brown eye colour was inherited as a dominant trait and blue eye colour as a recessive one, and, as a result, two blue-eyed parents were incapable of producing children with brown eyes. Although this doctrine was widely taught, it soon became apparent that occasionally blue-eyed parents could produce brown-eyed offspring and that eye colour was not inherited as a simple Mendelian trait.13 Indeed, recent studies suggest that eye colour is inherited as a polygenic trait, which, as yet, is incompletely understood.
Histologically, the cutaneous elements of oculodermal melanocytosis contain spindle and dendritic cells in the dermis resembling melanocytes migrating from the neural crest to the epidermis.74 In this respect oculodermal melanocytosis is similar to Mongolian spot, naevus of Ito, and blue naevus. Histopathological studies of affected eyes have shown the presence of pigmented stellate melanocytes distributed throughout the sclera and episcleral tissues together with increased numbers of benign plump dendritic monocytes within the choroid.75, 76, 77 An ultrastructural study of an affected iris demonstrated the presence of numerous melanocytes in the anterior border and iris stromal layers. Many of these melanocytes, in addition to a normal-sized melanosomes, contained large round macromelanosomes, which probably reflects a basic defect in melanogenesis within the cells.77
A young woman looks over her shoulder at us. She holds her head slightly to one side, there is a gleam in her greyish-blue eyes, and her lips are slightly parted and moist. On her head is a turban that she has wound from two pieces of material, one blue and one yellow, and she is adorned with a pearl earring. It is from this oversized jewel in the middle of the composition that the painting derives its title. 350c69d7ab