Exceptional Desoxyribose Nucleic Acid (DNA) Findings in a Sterile Dwarf Bull

In an extensive investigation of the cytological, cytochemieal, and dinieal features that are involved in the sterility of mammals (1-3), we have also made a study of so called dwarfism in cattle. I t is almost certain that in cattle, as in most other mammals, several different types of dwarfs occur (4) and it is unfortunate that relatively little is yet known concerning their genetic background. I t is clear however that, in some of its manifestations, dwarfism is linked with varying degrees of sterility (5), and this will explain our interest in the present case. The material in question stems from a dwarf bull that originated in a herd of pure bred Hereford cattle and constituted one of the individuals that is mentioned in a paper by Johnson, Harshiield, and McCone (5). The tissues were fixed in 10 per cent formalin and embedded in paratfm. We obtained several of the para~n blocks through the great kindness of Dr. L. E. Johnson and Dr. J. S. Harshfield. To serve as controls, tissues were also obtained from several normal bulls and were fixed in 10 per cent formalin, Carnoy, or Lavdowsky and embedded in paraffin. For the DNA analyses, sections cut from the dwarf and normal bull tissues and