Bwdq8^C57BL/6J
QTL Variant Detail

Summary

• QTL variant: Bwdq8^C57BL/6J
• Name: body weight in DDD mice, QTL 8; C57BL/6J
• MGI ID: MGI:5907375
• QTL: Bwdq8 Location: unknown Genetic Position: Chr5, Syntenic

Variant origin

• Strain of Specimen: C57BL/6J

Variant description

• Allele Type: QTL

Notes

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

J:242652

In the current study QTL mapping was performed for body weight using R/qtl in reciprocal F2 male populations between the heavier DDD/SgnRbrc (DDD) inbred mice and inbred C57BL/6J (B6) mice. Four significant QTL were identified on Chromosomes 1, 2, 5, and 17. QTL mapping was also performed for plasma testosterone levels to examine the effect of testosterone level on body weight in male mice. DDD/SgnRbrc mice have extremely high levels of circulating testosterone relative to other inbred strains.

150 male mice from each F2 reciprocal cross were used. Body weight was determined for DDD, B6 and F1 mice at the age of 13-14 weeks and for F2 mice at 11-12 weeks of age. Mice were euthanized with an overdose of ether immediately after weighing in the morning (from 10:00 a.m. to 12:00 a.m.). Blood was collected from the hearts of individual mice. In total, 117 microsatellite loci were genotyped and their chromosomal positions were retrieved from Mouse Genome Informatics (MGI, http://www.jax.org).

Single-QTL scans were performed by computing in 1-cM increments across the entire genome using cross direction (DB vs. BD) as a covariate. Threshold LOD scores for significant (P < 0.05) and suggestive (P < 0.63) linkages were determined by performing 1000 permutations (Lander and Kruglyak 1995). After single-QTL scans, two-QTL scans were performed. Finally, the combined effects of all QTL, including those that were significant and suggestive, were assessed using multiple-QTL models.

Table 2: Significant and suggestive QTL:

QTL Bwdq6 (body weight in DDD mice, QTL 6) mapped to Chromosome 1 with a LOD score of 5.77 peaking at 78.5 cM nearest marker D1Mit356. The 95% CI mapped between 67.5 and 91.5 cM. The DDD allele was associated with increased body weight at this locus.

QTL Bwdq7 (body weight in DDD mice, QTL 7) mapped to Chromosome 2 with a LOD score of 3.72 peaking at 72.8 cM nearest marker D2Mit494. The 95% CI mapped between 44.8-87.8 cM. The B6 allele was the high allele at this locus when inherited in a recessive or additive pattern.

QTL Bwdq8 (body weight in DDD mice, QTL 8) mapped to Chromosome 5 with a LOD score of 3.55 peaking at 52.5 cM nearest marker D5Mit239. The 95% CI mapped between 26.8-66.8 cM. The DDD allele was associated with increased body weight at this locus.

QTL Bwdq9 (body weight in DDD mice, QTL 9) mapped to Chromosome 17 with a LOD score of 5.22 peaking at 20.1 cM nearest marker D17Mit176. The 95% CI mapped between 11.1-30.1 cM.

The B6 allele was the high allele at this locus when inherited in a dominant or additive pattern.

Curator Note: The authors had equated the Chr 17 QTL identified in the current study with the Bwdq3 QTL identified on Chr 17 in a previous study. However, since congenic mice were used in the previous study, a differing mapping population, we have given the Chr 17 QTL identified here unique nomenclature - Bwdq9.

When QTL analysis was performed including the cross direction as an interactive covariate 2 suggestive QTL were identified on Chrs 2 and 3. No significant QTL x covariate interactions were found. Two-QTL scans revealed no significant pairwise interactions. A multiple regression analysis indicated that the detected QTL explain 30.94 % of body weight variation.

One suggestive QTL was identified for plasma testosterone level on Chromosome 5 with a LOD score of 2.47 at 52.2 cM. The DDD allele was associated with increased testosterone levels in a dominant mode of inheritance.

References

• Original: J:242652 Suto JI, et al., Quantitative trait loci that control body weight in DDD/Sgn and C57BL/6J inbred mice. Mamm Genome. 2017 Feb;28(1-2):13-19
• All: 1 reference(s)