Genetic mapping of a dwarf mutation rat of in Miniature Rat Ishikawa (MRI)

2002 Fiscal Year Final Research Report Summary

• Project/Area Number: 13671161
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Endocrinology
• Research Institution: Saitama Medical School
• Principal Investigator: KAWAZU Shoji Saitama Medical School, medicine, Professor, 医学部, 教授 (30134547)
• Co-Investigator(Kenkyū-buntansha): KOMEDA Kjuro Tokyo Medical Univercity, medicine, Professor, 医学部, 教授 (90074533) ; OMURA Eiji Saitama Medical School, medicine, Lecturer, 医学部, 講師 (90119917)
• Project Period (FY): 2001 – 2002
• Keywords: Mutant / Mapping / Rat / Dwarfism

Research Abstract

A novel autosomal recessive dwarf mutation, miniature rat Ishikawa (mri), was discovered in, a closed colony of Wistar rats. The mutant strain has recently been established as a segregating inbred, named Miniature Rat Ishikawa (MRI). In the present study, we characterized the phenotype of MRI and also performed genetic analyses of the mutation. The homozygous mutants (mri/mri) grew retarded among 60 to 70% of normal sized littermates. Their longitudinal growth was especially impaired. Genetic analyses placed the mri locus in a genomic segment of 1.2cM on rat chromosome 14. Comparative mapping suggested that the orthologs of mri are located on mouse chromosome 5 and human chromosome 4p14-q21. These data suggest that the mri mutation may be a novel dwarf mutation and that MRI should serve as a useful animal model for dwarfism in humans.