Genetic Resistance to Deficiency of Riboflavin in the Chick

GREAT differences in the response of individuals to different diets, or to certain deficiencies in the diet, are normally expected, and are commonly assumed to result, in part, from differences in genotype. Striking results of selection for resistance to a nutritional deficiency were obtained by Serfontein and Payne (1934) when, with only one generation of selection, they were able to segregate fowls 18.6 percent of whose chicks developed “slipped tendon” (perosis), as compared with 50 percent among chicks from parents which had been susceptible to the disorder. In view of a later study by Wilgus, Norris and Heuser (1937) we may assume that much of this difference was the result of differences in genetic resistance to a deficiency of manganese in the diet. A difference between breeds in their requirement for vitamin B1 (thiamine) was later demonstrated by Lamoreux and Hutt (1939). They found that White Leghorns consistently had a . . .