Hereditary chondrodystrophy in the turkey

A new form of chondrodystrophy was observed in an inbred line of large weight white turkeys. It is characterized by shortened and thickened long bones of the legs and wings and proportionally shortened beaks. The absence of some terminal phalanges was noted in about half of the mutants. A hydrocephalous condition was observed in a few mutants but was not found in normal embryos. The chondrodystrophy is caused by an autosomal recessive semi-lethal gene designated chm. Only three chm chm individuals have hatched normally but others have been assisted out of the shell and have survived for varying periods of time. Of six that survived to mature age, all were sterile. A slightly different form of chondrodystrophy was observed in medium-weight turkeys from three sources. This type, which did not have the missing phalanges or hydrocephalic expression, was also caused by a recessive gene which was different from chm. Phenotypically, they differed from s s embryos (Asmundson, 1944) by shortening of the beak and failure to hatch.