Mfq4^LG/J
QTL Variant Detail

Summary

• QTL variant: Mfq4^LG/J
• Name: muscle fiber QTL 4; LG/J
• MGI ID: MGI:6379062
• QTL: Mfq4 Location: unknown Genetic Position: Chr2, Syntenic

Variant origin

• Strain of Specimen: LG/J

Variant description

• Allele Type: QTL
• Inheritance: Not Specified

Notes

Mapping and Phenotype information for this QTL, its variants and associated markers

J:251734

Muscle fiber cross-sectional area (CSA) and proportion of different fiber types are important determinants of muscle function and overall metabolism. The authors aimed to map QTL affecting differences in soleus muscle fiber traits between the LG/J and SM/J mouse strains.

Fiber number, CSA, and proportion of oxidative type I fibers were assessed in the soleus of 334 genotyped female and male mice of the F34 generation of advanced intercross lines (AIL) derived from the LG/J and SM/J strains. To increase the QTL detection power, these data were combined with 94 soleus samples from the F2 intercross of the same strains. The following phenotypes were assessed: muscle fiber number (type I and IIA) and percent of type I muscle fibers, CSA of type I and type IIA fibers. Muscle fiber traits were manually analyzed with ImageJ software.

Mice were genotyped using a custom-designed SNP array that included 4,610 polymorphic SNPs that were approximately evenly distributed across the genome. The genome-wide association analysis was performed in the combined population of the F34 and recently published F2 intercrosses using the R package QTLRel and mapped to genome coordinates from GRCm38.p3.

Genome-wide association analysis mapped four QTL affecting the properties of muscle fibers:

QTL Mfq3 (muscle fiber QTL 3) maps to Chr 11: 28.0 31.5 Mb. The LG/J allele confers increased CSA of type I and type IIA fibers at Mfq3. Mfq3 was previously identified in an F2 intercross of the same parental strains (Carroll AM, et al., 2011). The current study fine maps the location to a narrower QTL interval. In both studies, Mfq3 exhibited male specificity in both type I and IIA fibers.

QTL Mfq4 (muscle fiber QTL 4) maps to Chr 2: 158.8 - 162.5 Mb. The SM/J allele confers greater percentage of type I fibers at Mfq4.

QTL Mfq5 (muscle fiber QTL 5) maps to Chr 3: 33.6 - 40.0 Mb. The SM/J allele confers increased CSA of type I and type IIA fibers at Mfq5.

QTL Mfq6 (muscle fiber QTL 6) maps to Chr 4: 57.7 62.7 Mb. The LG/J allele confers greater percentage of type I fibers at Mfq6.

References

• Original: J:251734 Carroll AM, et al., Fine-mapping of genes determining extrafusal fiber properties in murine soleus muscle. Physiol Genomics. 2017 Mar 01;49(3):141-150
• All: 1 reference(s)