Genotypic Control of Feather Color Pattern as Linked Gene upon the Melanophores*

T HAS been shown by grafting potential melanophores from one embryo to I another of a genetically different breed of fowl or species of bird that the color or color pattern produced in the host feather is invariably like that of the donor breed or species (RAWLES 1939; WILLIER and RAWLES 1940). In other words, the coloration or color pattern produced seems to depend upon the genotypic constitution of the donor melanophore. To establish genotypic constitution as the controlling factor it was decided to test the effects of melanophores derived from embryos of a hybrid cross which shows sex-linked differences in the coloration of the plumage. The F1 hybrids obtained by mating a Barred Plymouth Rock female with a Rhode Island Red male seemed to be ideal for this purpose.' In birds from this cross the juvenile and adult contour feathers of the female are non-barred and predominantely either red or black, the relative proportions of which in a given bird and feather are quite variable, whereas in the males they are typically barred black and white like the female parent. The down plumage is black on the dorsal surface of the body in both sexes except for a white feathered area on top of the head in the males. The purpose of the present paper is (I) to analyze the differences in phenotypic color effects produced in host feathers by grafting melanoblasts from male and female hybrid embryos, ( 2 ) to determine whether the sex of the host has any influence on the color pattern produced and (3) to compare the patterns produced in the host chick with patterns developed in the donor chicks which furnished the melanophores. In this way it is possible to determine the extent to which the melanophore acts independently and how far it comes under the influence of the individual feather germs of the host.