Materials and methods

Abstract

Mice obtained for this study were products of pudgy breeding pairs from Jackson Laboratories, Bar Harbor, Maine. For the affected pudgy mice, heterozygous unaffected littermates served as controls. An affected pudgy mouse (pu/pu) can be identified at birth since it is approximately three-quarters the length of its non-affected littermates (pu/+) and has a markedly shortened, twisted tail. The mice were sacrificed by intraperitoneal injections of sodium pentobarbital. Vertebral and rib assessments were performed in 68 mice, 37 affected (pu/pu) and 31 non-affected (pu/+) age-matched siblings from the late embryo to 3 months of age. There were eight sets of births (litters) in which two or more of the sibling littermates were affected, allowing for a comparison of rib and vertebral anomalies in pudgy mice from the same mother and same pregnancy as well as with all other pudgy mice.