PRESENCE, ISOLATION AND CHARACTERIZATION OF YOLK DNA FROM CHICKEN EGGS

Yolk DNA was detected with immunocytochemistry in fertilized chicken e ggs. Yolk spheres were purified with Ficoll-400 density gradient centr ifugation, followed by extraction of DNA therein. Yolk DNA is sensitiv e to various restriction endonucleases, but shows no obvious bands, de monstrating its sequence heterogeneity. There is only a little, if any , methylated CpG in yolk DNA, judging from MspI and HpaII digestion. S outhern blot indicated that the sequence of yolk DNA accounts for a sm all portion of that of genomic DNA. Its uniqueness suggests that yolk DNA may play a crucial role in early development of chickens.