Morphological characterization of the skeletal malformations caused by
the Dh gene was carried out. Skeletal preparations from newborn mice
of Dh/Dh, Dh/+ and +/+ genotypes, and adult Dh/+ mice were examined. T
he Dh gene induced skeletal deformities at the axial regions from the
thorax to the tail. Attachment of the ribs to the sternum was sometime
s irregular, and normal segmentation of the sternum was also disrupted
. Abnormal fusion of the ventral part of the rib was observed in some
cases. Lumbar vertebrae were fewer in number and abnormal in shape. Al
though it was rare, a curled tail was also observed due to distortion
of the caudal vertebrae.