Mapping Data

Experiment

• Experiment
  TEXT-QTL-Candidate Genes
• Chromosome
  9
• Reference
  J:99474 Suto J, Apolipoprotein gene polymorphisms as cause of cholesterol QTLs in mice. J Vet Med Sci. 2005 Jun;67(6):583-9
• ID
  MGI:3583096

Genes

Gene	Assay Type
Cq4	visible phenotype
Cq5	visible phenotype
Apoa4	reported elsewhere

Notes

• Experiment
  Linkage analysis was performed on 3 separate F2 crosses in 3 previous studies: J: 54322, J:87328 and J:94251 to map QTLs associated with plasma cholesterol levels. Cq1, Cq2, and Cq6 mapped to mouse Chromosome 1, Cq3 mapped to mouse Chromosome 3, and Cq4 and Cq5 mapped to mouse Chromosome 9.
  
  Cq2 and Cq6 map to the same location on distal mouse Chromosome 1 at approximately 100 cM. Cq2 was identified in a (C57BL/6J x KK-A^y)F2 intercross and Cq6 was identified in a (C57BL/6J x RR)F2 intercross. Apoa2 wasinvestigated as a possible candidate gene. The Apoa2^b allele is found in KK and RR strains and is associated with increased cholesterol levels while inbred strain C57BL/6J carries the Apoa2^a allele. It is thought that the Apoa2^b allele may be responsible for the QTL effects of Cq2 and Cq6.
  
  Inbred strains A/J and SM/J carry the Apoa2^c allele. It was previously unknown whether the Apoa2^a and Apoa2^c alleles had the same or different influences on plasma cholesterol level. An F2 intercross between congenic strains C57BL/6J-Apoa2^a and C57BL/6J-Apoa2^c revealed no physiological differences between the Apoa2^a and Apoa2^c alleles. Therefore, the Apoa2^b allele confers increased plasma cholesterol compared to the Apoa2^a and Apoa2^c alleles.
  
  Cq4 and Cq5 map to the same location on mouse Chromosome 9 at approximately 27 cM and Apoa1 and Apoa4 were investigated as possible candidate genes. Cq4 was identified in a (C57BL/6J x KK-A^y)F2 intercross and Cq5 was identified in a (KK x RR)F2 intercross. Sequence analysis of Apoa1 revealed that polymorphic differences between the involved strains did not correlate to cholesterol phenotype. Analysis of Apoa4 revealed a silent polymorphism (C771T) that exhibits complete correlation to cholesterol phenotype. Inbred strain KK carries the T allele whereas inbred strain C57BL/6J and RR carry the C allele. Another polymorphism in Apoa4 was detected involving a 12 nucleotide insertion encoding Glu-Gln-Ala/Val-Gln. Inbred strain KK carries 3 repeats, inbred strain C57BL/6J carries 4 repeats, and inbred strain RR carries 5 repeats. However, it could not be determined if this particular polymorphism explains the QTL effect of Cq4 and Cq5 on cholesterol levels.