Further studies on the cell populations of an intersex horse.

An intersex horse exhibiting cell types of different sex chromosome constitution was subjected to further studies in order to determine whether the house was a mosaic or a chimera. Cultures of gonadal tissue and peripheral blood revealed mainly 64/XX and 64/XY cells, the former predominating in both tissues. The frequency of drumstick-bearing poly-morphonuclear neutrophils in the intersex horse was similar to that noted in normal mares. Blood type analysis using 17 naturally occurring agglutinins and hemolysins revealed partial agglutinations with three antibodies for the factors of the A system (anti-A, anti-F, and anti-I), and partial hemolysis with anti-Fr(3) suggesting erythrocyte chimerism probably resulting from intrauterine interchange of blood cell precursors as noted in other domestic animals. On the other hand, the presence of XX and XY cells in cultures of gonads which in our intersex horse were apparently devoid of germ cells, would seem to indicate wholebody chimerism resulting from double fertilization or blastocyst fusion.