Pleiotropisms associated with alleles of the C locus in the domestic fowl.

Pleiotropisms associated with the recessive white (c) and albino (ca) alleles at the C locus of the domestic fowl were investigated. Hatchability of fertile eggs was not significantly different for the colored (C+/c, C+/ca), recessive white (c/ca), and albino (ca/ca) chicks; however, late embryonic mortality was higher in ca/ca embryos P less than or equal to .005). Albinos exhibited shorter down lengths (P less than or equal to .01), higher incidences of subcutaneous hemorrhage and inflammation (P less than or equal to .01) and an increased incidence of yolk sac protrusions (P less than or equal to .01). Suppressed body weights (P less than or equal to .01) were evident at all times, except at hatching, in both male and female albinos reared in batteries. Recessive white females also exhibited smaller body weights than colored chicks at 7 and 8 weeks of age in battery trials (P less than or equal to .01). Significant suppression of body weights occurred in albinos only at 4 weeks of age in trials where floor rearing was used. Mortality in albinos was also significantly higher, particularly under floor rearing conditions (P less than or equal to .01). In addition, both feed consumption and feed utilization were reduced in albinos (P less than or equal to .01). These data suggest that melanin synthesis is an important component in the expression of a number of important physiological traits and that the C locus exerts a previously undefined regulatory influence on such traits.