Inheritance of blood ring, an early embryonic failure in the turkey.

Blood ring describes an early embryonic failure that has been observed in a subline of Wrolstad Medium White turkeys. The condition can be detected by candling at approximately 96 h of incubation when shell pigmentation is minimal. The condition, macroscopically visible as early as 66 h, is characterized by the presence of uncoalesced blood islands, an erythrocyte-engorged sinus terminalis, and the absence of an extra-embryonic circulatory system. The sex ratio of progeny from the mating of heterozygous parents did not deviate from a 1:1 ratio and no blood ring embryos resulted from the matings of heterozygous males and normal females. The disorder is inherited as an autosomal recessive trait and appears to be similar to a condition observed in both normal-sized and dwarf (dw) Single Comb White Leghorn chickens. The symbol blr is suggested for the gene.