Live haploid-diploid and other unusual mosaic chickens (Gallus domesticus).

Sixteen haploid-diploid chickens, four diploid-triploids, and one haploid-diploid-triploid chicken have been found in a layer line of crossbred origin. Live haploid-euploid vertebrates have not been reported previously. Flow cytometric analysis revealed 1-80% haploid red blood cells (RBCs) in the haploid-euploid chickens and 5-30% triploid RBCs in the diploid-triploids. Mosaic cell lines were also found in leukocytes and many tissues. The haploid-diploid chickens were all phenotypically normal and fertile, but the phenotype and fertility of the diploid-triploid chickens depended on their sex-chromosome complements and the ratio of diploid to triploid cells. The haploid cell lines are thought to originate from supernumerary spermatozoa, and the diploid-triploids from binucleated oocytes with meiotic errors. It is likely that genetic factors are partly responsible for the occurrence of these mosaic chickens.