Ifbw1^C57BL/6J
QTL Variant Detail

Summary

• QTL variant: Ifbw1^C57BL/6J
• Name: interfrontal bone width 1; C57BL/6J
• MGI ID: MGI:6314304
• QTL: Ifbw1 Location: Chr4:123395188-123892985 bp Genetic Position: Chr4, Syntenic

Variant origin

• Strain of Specimen: C57BL/6J

Variant description

• Allele Type: QTL
• Inheritance: Not Specified

Notes

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

J:275176

The interfrontal bone (IF) is a minor skeletal trait residing between the frontal bones. IF is considered a quasi-continuous trait.

In order to identify genes involved in IF bone development, the authors surveyed inbred strains of mice for the prevalence of IF and performed QTL mapping studies.

Archived mouse skulls from a mouse phenome project (MPP) were available for this study. 27 inbred strains were investigated with 620 mice examined for each strain. Skulls were viewed dorsally and the IF was measured using a zoom stereomicroscope equipped with a calibrated reticle. Additionally, a two generation cross between C3H/HeJ and C57BL/6J mice was performed to generate a panel of 468 F2 mice. F2 mice were phenotyped for presence or absence of IF bone and among mice with the IF bone maximum widths and lengths were measured.

F2 mice were genotyped for 573 SNP markers informative between C3H/HeJ and C57BL/6J and subjected to linkage map construction and interval QTL mapping.

Strain dependent differences in the prevalence of IF bones were observed. Overall, 77.8% or 21/27, of the inbred strains examined had IF bones. Six strains (C3H/HeJ, MOLF/EiJ, NZW/LacJ, SPRET/EiJ, SWR/J, and WSB/EiJ) lack IF bones. Among the strains with IF bones, the prevalence ranged from 100% for C57BL/6J, C57/LJ, CBA/J, and NZB/B1NJ and down to 5% for strains such as CAST/Ei.

QTL mapping using R/QTL identified several significant QTL for IF bone length and width (all coordinates relative to Mouse Genome Build 36):

QTL interfrontal bone length 1 (Ifbl1) maps to 75.0 cM on Chr 3 (c3.loc75) with a peak LOD score of 4.20.

QTL interfrontal bone length 2 (Ifbl2) maps to Chr4:123501395 - 123999192 bp with a peak LOD score of 5.82 at

rs27567417 (gnf04.119.329; 68.5 cM).

QTL interfrontal bone length 3 (Ifbl3) maps to Chr7:120484415 - 120693266 bp with a peak LOD score of 5.78 at rs6322316 (61.9 cM).

QTL interfrontal bone length 4 (Ifbl4) maps to Chr11:119851494 - 120035454 bp with a peak LOD score of 4.57 at rs6346368 (99.4 cM).

QTL interfrontal bone length 5 (Ifbl5) maps to Chr14:60723374 - 61769264 bp with a peak LOD score of 7.21 at rs3699179 (38.2 cM).

QTL interfrontal bone width 1 (Ifbw1) maps to Chr4:123501395 - 123999192 bp with a peak LOD score of 6.95 at gnf04.119.329 (rs27567417; 68.5 cM).

QTL interfrontal bone width 2 (Ifbw2) maps to Chr7:120484415 - 120693266 bp with a peak LOD score of 5.18 at rs6322316 (61.9 cM).

QTL interfrontal bone width 3 (Ifbw3) maps to Chr11:119851494 - 120035454 bp with a peak LOD score of 5.44 at rs6346368 (99.4 cM).

QTL interfrontal bone width 4 (Ifbw4) maps to Chr14:60723374 - 61769264 bp with a peak LOD score of 9.03 at rs3699179 (38.2 cM).

The selection of the C57BL/6J and C3H/HeJ strains for QTL mapping was based upon each strain falling within the extreme state of having or not having IF bones, respectively. The authors found that IF bone lengths and widths were highly correlated traits, such that IF bones with greater lengths tended to have greater widths. This observation of IF bone lengths and widths being highly correlated traits was also evident in the peak LOD values being associated with the same markers on chromosomes 3, 4, 7, and 11.

References

• Original: J:275176 Zimmerman H, et al., Interfrontal Bone Among Inbred Strains of Mice and QTL Mapping. Front Genet. 2019;10:291
• All: 1 reference(s)