Localization of am3 using EL congenic mouse strains.
EL/Sea mice have 100% incidence of the absence of third molars (M3). Our previous linkage analysis using EL/Sea and MSM/Msf mouse strains provides statistical evidence of a major locus for the absence of M3, designated am3, of EL/Sea at the middle region of chromosome 3. To obtain independent evidence for linkage and more precisely determine the location of the am3 locus, we generated EL/Sea congenic strains for am3 in which the restricted interval of chromosome 3 of EL/Sea was replaced by an MSM/Msf-derived homologue. EL/Sea congenic mice that were either heterozygous or homozygous for the MSM/Msf-derived interval exhibited a significant decrease in the incidence of the absence of third molars, confirming previous genome scan results. These results confine the am3 locus to an approximately 4.4-cM region, and demonstrate that other unmapped genes are also involved in the absence of M3 in EL/Sea mice.
Shimizu
T
T
Department of Pediatric Dentistry, Nihon University School of Dentistry at Matsudo, 2-870-1 Sakaecho-Nishi, Chiba 271-8587, Japan. takehiko@mascat.nihon-u.ac.jp
Han
J
J
Asada
Y
Y
Okamoto
H
H
Maeda
T
T
D000818:Animals; D000848:Anodontia / Q000235:genetics*; D002874:Chromosome Mapping; D033481:Chromosomes, Mammalian; D004252:DNA Mutational Analysis; D005787:Gene Frequency; D051379:Mice; D020297:Mice, Congenic; D008964:Molar, Third / Q000002:abnormalities*