The SEA/GnJ strain harbors
two mutant alleles
of the Bmp5 gene
and displays abnormal developmental phenotypes. Mice
homozygous for Bmp5 (se/se) manifest short ears while Bmp5 (se/+)
have long ears. To improve reproductive performance, SEA/GnJ is
maintained by inbreeding Bmp5 (se/se) x Bmp5 (+/se).
Offspring of both genotypes are produced.