Rous Sarcoma Virus associated with Parthenogenesis in Turkey Eggs

Abstract

SPONTANEOUSLY occurring parthenogenesis in unfertilized eggs of the domestic turkey, Meleagris gallopavo Linnaeus, was first noted¹ at the Agricultural Research Center, Beltsville, Maryland, in 1952. Unselected Beltsville Small White turkey hens, as virgins, produced eggs of which 16 per cent showed parthenogenetic development following an incubation period of 9–10 days. This development consisted chiefly of a thickened sheet of unorganized and often multinucleated cells which covered varying areas of yolk surfaces. Usually, these cells did not attain the degree of organization necessary for blood formation and only on rare occasions were embryos noted. Through a system of selective breeding a strain of Beltsville Small White turkeys has been developed which regularly, as virgins, produce eggs of which 40 per cent can be expected to show some degree of parthenogenetic development. The greatest increase, by percentage, has been in the increased number of eggs showing a high degree of organized development. In 1959, embryos developed in 342 of the 2,926 eggs tested. This represented 11.7 per cent embryos, an increase amounting to 57 times that observed in 1952. Included were 12 poults which were helped from the shell and survived for some time (Olsen²).