The tail of dominant short tail heterozygotes varies from very short, approximately an eighth to a quarter of an inch and wound close to the body, to approximately half and inch and tightly kinked or curled only at the distal end. They are slightly smaller than normal littermates and some, but not all, have a white belly spot or iris colobomas or corneal holes. Female and male heterozygotes can breed and live a normal lifespan. When outcrossed to CAST/EiJ no F1 offspring or N2 offspring are found with the phenotype, while affected mutants are found when outcrossed to C3H/HeJ, but at reduced penetrance with approximately 10% or fewer affected.
The dominant short tail (Dsht) mutation arose spontaneously in the strain B6.129S2Tap1tm1Arp/J in 1999. This mutant subline was backcrossed to C57BL/6J then sibling intercrossed and the Tap1tm1Arp was bred out of this line. After many generations of sibling intercrossing heterozygotes with wildtype siblings, the maintenance of this line was changed to breeding to C57BL/6J at each generation. In 2013 this strain reached generation N5.
When using the B6.Cg-Dsht/GrsrJ mouse strain in a publication, please cite the originating article(s) and include JAX stock #012654 in your Materials and Methods section.