Experiment
QTL mapping was performed on 328 (SM/J x NZO/HlLt)F2 intercross animals to identify loci associated with obesity phenotypes. Parental strain SM/J is small and lean while parental strain NZO/HlLt is obese.
Three loci mapped to mouse Chromosome 1: Obq7, Obq8, and Obq9.
Obq7 is linked to gonadal fat percentage (LOD = 6.9, stronger effect in males), mesenteric fat percentage (LOD = 6.0), and retroperitoneal fat percentage (LOD = 2.4) at 28.7 cM. NZO-derived alleles confers increased gonadal fat percentagein a recessively or additively inherited fashion at Obq7.
Obq8 is linked to retroperitoneal fat percentage (LOD = 6.4) and adiposity index (LOD = 5.7) at 69.1 cM with the NZO-derived allele conferring increased adiposity in a dominantly or recessively inherited fashion.
Obq9 is linked to mesenteric fat percentage (LOD = 6.7), adiposity index (LOD = 6.2), and inguinal fat percentage (LOD = 2.5) at 88.4 cM with the NZO-derived allele conferring increased adiposity in an additive fashion.
Obq10 maps tomouse chromosome 2 and is linked to adiposity index (LOD = 5.4, stronger effect in males), gonadal fat percentage (LOD = 7.4, stronger effect in males), mesenteric fat percentage (LOD = 7.4), and retroperitoneal fat percentage (LOD = 3.0) at 58.1 cM withthe NZO-derived allele conferring increased adiposity in an additive fashion. Obq10 may also have an effect on body length.
On mouse Chromosome 5, Obq11 and Obq12 map to 10 cM and 29 cM, respectively.
Obq11 is linked to adiposity index (LOD = 3.1, inmales), mesenteric (LOD=4.4), gonadal (LOD = 4.1), retriperitoneal (LOD = 3.3), and inguinal (LOD = 1.7) fat percentages.
Obq12 is linked to adiposity index (LOD = 3.7, in males), mesenteric (LOD = 5.3), gonadal (LOD = 4.5), retriperitoneal (LOD = 2.0), and inguinal (LOD = 2.2) fat percentages. NZO-derived alleles confer increased adiposity at Obq11 and Obq12 in an additive fashion.
On mouse Chromosome 6, Obq13 and Obq14 map to 26.8 cM and 43.5 cM, respectively.
Obq13 is linked to adiposity index (LOD= 8.8), mesenteric (LOD = 9.3), gonadal (LOD = 6.0), inguinal (LOD = 6.2), and retroperitoneal (LOD = 5.1) fat percentages, and Obq14 is linked to adiposity index (LOD=6.4), mesenteric (LOD = 9.2), gonadal (LOD = 4.1), inguinal (LOD = 4.5), and retroperitoneal (LOD = 3.9) fat percentages. NZO-derived alleles confer increased adiposity in an additive fashion at Obq13 and Obq14. A candidate gene for Obq13 is neuropeptide Y (Npy). Analysis of Npy sequence revealed polymorphisms between SM/J and NZO/HlLt but does not appearto explain the phenotypic differences between the strains.
Obq15 maps to mouse Chromosome 7 at 51.4 cM and is linked to adiposity index (LOD = 6.3), gonadal (LOD = 8.1, stronger effect in males), inguinal (LOD = 4.2), mesenteric (LOD= 2.9), and retroperitoneal (LOD = 2.8) fat percentages with the NZO-derived allele contributing to increased adiposity in a dominant fashion.
A locus linked to adiposity index (LOD = 5.8), inguinal (LOD = 8.8, stronger in males), gonadal (LOD = 3.5), retroperitoneal (LOD = 3.1), and mesenteric (LOD = 3.0) fat percentages mapped to mouse Chromosome 17 at 8.7 and colocalizes with Obq4, a previously mapped obesity QTL (Taylor, J:39947).
11.20.2014 Curator's Note: Because the QTL cited here as colocalizing with Obq4 was originally mapped using a different cross we consider the current study a separate mapping study. We have named the QTL mapping here, to mouse Chromosome 17 at 8.7cM, Obq36. SM/J-derived alleles confer increased adiposity in a dominant or overdominant fashion at Obq36.
A suggestive locus mapped to mouse Chromosome X at 49 cM and is linked to adiposity index in males (LOD = 2.7) and gonadal fat percentage (LOD = 4.1). SM/J-derived alleles appear to increase gonadal fat percentages in males at this locus.
Analysis Tools