MOLECULAR GENETICS OF AVIAN PROTEINS, II. CONTROL GENES AND STRUCTURAL GENES FOR EMBRYONIC AND ADULT HEMOGLOBINS

Abstract

Early chicken embryos have a hemoglobin that is electrophoretically, structurally, and functionally different from that of late embryos and adults. Synthesis of embryonic hemoglobin is "turned off after 5 days of incubation in White Leghorn, New Hampshire, and Columbian chickens; in bantam chickens the embryonic hemoglobin synthesis continues 12-24 hr later than in the other chicken breeds; in the turkey, adult hemoglobin begins to appear only after 8 days of incubation. In the red-winged blackbird, adult and embryonic hemoglobins are synthesized together from the very beginning of erythropoiesis. Therefore, it is postulated that some kind of "control genes" exist which determine when[long dash]or whether[long dash]adult and embryonic hemoglobins are produced. In addition, there may also be control genes that regulate the total amount of a particular polypeptide chain that is produced; 1 individual pheasant was found with a condition resembling thalassemia in the human, which has been suggested to be due to a "tap gene" mutation.