This chemically-induced multigenic deletion in Chromosome 1, which includes Mlph in the deletion, causes embryonic lethality in homozygotes. Compound heterozgyotes of Mlphln/l1Rk3 are viable but have the diluted coat color caused by Mlph mutations.
The In(1)1Rk inversion was radiation-induced in a DBA/2J male and this male was immediately bred to a C57BL/6J female. Many years later, a male homozygous for In(1)1Rk was exposed to 0.3 mg/kg triethylene melamine and mated to females heterozygous for splotch and homozygous for leaden (Pax3Sp Mlphln/Pax3+ Mlphln) on a predominantly C57BL/6J background in order to screen for radiation-induced lethal mutations in the In(1)1Rk-bearing chromosome. The offspring with the splotch phenotype, which were necessarily In(1)1Rk + +/+ Pax3Sp Mlphln, were intercrossed generating live offspring that all had the splotch phenotype (In(1)1Rk + +/+ Pax3Sp Mlphln). The absence of Pax3+ pups proved the presence of a recessive lethal mutation on the In(1)1Rk-bearing chromosome, which was designated l1Rk3. The repulsion heterozygotes (l1Rk3 + +/+ Pax3Sp Mlphln), identified by the phenotypic presence of splotch and absence of the recessive leaden phenotype, were intercrossed at each generation to maintain this strain and embryos were generated for cryopreservation from repulsion heterozygotes. The cryo-recovered pups that have the splotch phenotype but not the leaden phenotype are the repulsion heterozygotes that should be used to maintain this line.
|Allele Name||lethal, Chr 1, Roderick 3|
|Allele Type||Chemically induced (other)|
|Gene Symbol and Name||l1Rk3, lethal, Chr 1, Roderick 3|
|Strain of Origin||Not Specified|
|General Note||This homozygous recessive lethal mutation was induced using triethylene melamine at 0.3 mg/kg.|
|Molecular Note||Sequence analysis of cDNA showed this allele comprises, minimally, a deletion of the coding region of Mlph, resulting in no expression of Mlph transcripts.|