A novel partial t haplotype with a brachyury-independent effect on tail phenotype

The btm (brachyury-interacting tail length modifier) mutation was discovered in strain MOL-NIS derived from Japanese wild mice (Mus musculus molossinus) as an autosomal recessive mutation. Homozygotes for this mutation show a short tail phenotype and, moreover, this mutation causes the tailless character by interacting with the T (brachyury) gene on Chromosome (Chr) 17. Our linkage tests and RFLP analyses suggest that btm is located within the t complex on Chr 17 and represents a new partial t haplotype.