Experiment
Linkage analysis using 92 microsatellite markers was performed on 419 animals from an M16i x (CAST/Ei x M16i)F1 backcross to map QTLs associated with growth characteristics such as organ weight and limb length. Parental strain M16i is a long-term selection line for rapid 3- and 6- week weight gain. QTLs reaching the 5% significance threshold are reported. Several of these loci exhibit pleiotropic effects. Markers associated with the confidence interval are given if available.
On mouse Chromosome 1, linkage to organ weight (Orgwq1) mapped to 63 cM near D1Mit140 (LOD=14.51). The QTL interval of Orgwq1 spans 53 cM (D1Mit9) - 71 cM (D1Mit140). M16i-derived alleles confer decreased heart and kidney weights and increased spleen weight at Orgwq1. Linkage to limb length (Lmblgq1) mapped to 67 cM near D1Mit140 (LOD=13.62). The QTL interval of Lmblgq1 spans 57 cM - 75 cM. M16i-derived alleles confer decreased length of the femur, tibia, humerus, and ulna. Potential candidate genes for Lmblgq1 are Gbx2, En1, and Myog.
On mouse Chromosome 2, linkage to organ weight mapped to 34 cM (Orgwq2) and 65 cM (Orgwq3) near D2Mit61 (LOD=26.10) and D2Mit164, respectively. The QTL range of Orgwq2 spans 1 cM (D2Mit1) - 55 cM (D2Nds1) and the QTL range of Orgwq2 spans 60 cM (D2Mit133) - 69 cM (D2Mit224). M16i-derived alleles confer increased spleen weight at Orgwq2 and increased liver weight at Orgwq3.
On mouse Chromosome 3, linkage to organ weight mapped to 34 cM (Orgwq4) and 75 cM (Orgwq5) near D3Mit46 (LOD=5.38) and D3Mit31, respectively. The QTL range of Orgwq4 spans 26 cM (D3Mit46) - 75 cM (D3Mit31) and the QTL range of Orgwq5 spans 41 cM (D3Mit10)- 75 cM (D3Mit31). M16i-derived alleles confer increased heart and liver weights at Orgwq4 and decreased heart and kidney weight at Orgwq5. Suggestive linkage to limb length mapped to 59 cM on mouse Chromosome 3 (LOD=3.02 at D3Mit10) with M16i-derived alleles conferring decreased tibia and ulna length at this locus.
On mouse Chromosome 4, linkage to organ weight mapped to 60 cM (Orgwq6) near D4Mit27 (LOD=4.46). The QTL range of Orgwq6 spans 46 cM - 76 cM. M16i-derived alleles confer increased spleen weight at Orgwq6.
Suggestive linkage to organ weight was detected at 1 cM on mouse Chromosome 5 (LOD=2.3) with M16i-derived alleles conferring increased heart, liver, spleen, and kidney weights. Linkage to limb length mapped to 27 cM (Lmblgq2) near D5Mit48 (LOD=7.47). The QTL range of Lmblgq2 spans 13 cM - 41 cM. M16i-derived alleles confer increased length of the humerus and ulnaat Lmblgq2. Potential candidate genes for Lmblgq2 are Ssq, Lx, Hx, and Tbx5.
Suggestive linkage to organ weight was detected at 46 cM on mouse Chromosome 6 (LOD=2.18) with M16i-derived alleles conferring increased spleen weight.
On mouse Chromosome 7,linkage to limb length mapped to 65 cM (Lmblgq3) near D7Mit37 (LOD=5.05). The QTL range of Lmblgq3 spans 43 cM (D7Mit55) - 79 cM (D7Mit37). M16i-derived alleles confer decreased femur, tibia, humerus, and ulna lengths at this locus.
On mouse Chromosome9, linkage to organ weight mapped to 29 cM (Orgwq7) near D9Mit2 (LOD=7.55). The QTL range of Orgwq7 spans 21 cM - 39 cM. M16i-derived alleles confer increased liver, spleen, and kidney weights at this locus.
On mouse Chromosome 10, linkage to limb length mapped to 31 cM (Lmblgq4) near D10Mit31 (LOD=3.94). The QTL range of Lmblgq4 spans 18 cM (D10Mit16) - 41 cM (D10Mit31). M16i-derived alleles confer decreased femur, tibia, and humerus length at Lmblgq4. Suggestive linkage to organ weight was detected at33 cM near D10Mit31 with M16i-derived alleles conferring increased heart and spleen weight at this locus.
On mouse Chromosome 11, linkage to organ weight mapped to 24 cM (Orgwq8) near D11Mit63 (LOD=6.27). The QTL range of Orgwq8 spans 14 cM (D11Mit63)- 49 cM (D11Mit5). M16i-derived alleles confer increased liver, spleen, and kidney weights at Orgwq8. Suggestive linkage to limb length was detected at 12 cM near D11Mit63 (LOD=2.11) with M16i-derived alleles conferring increased femur, tibia, and humeruslengths.
On mouse Chromosome 12, linkage to limb length mapped to 32 cM (Lmblgq5) near D12Nds11 (LOD=3.96). The QTL range of Lmblgq5 spans 16 cM (D12Nds11) - 47 cM (D12Mit5). M16i-derived alleles confer increased femur, tibia, and ulna lengths at Lmblgq5.
Suggestive linkage to limb length was detected at 25 cM on mouse Chromosome 14 near D14Mit10 (LOD=2.77) with M16i-derived alleles conferring decreased tibia and humerus lengths. M16i alleles confer increased ulna lengths in males and decreased ulna lengths in females at this locus.
Suggestive linkage to organ weight and limb length mapped to 43 cM (LOD=3.11 near D15Mit29) and 29 cM (LOD=2.16 near D15Mit121) on mouse Chromosome 15, respectively. M16i-derived alleles confer increased heart, liver, andspleen weights at 43 cM, and confer increased tibia, humerus, and ulna lengths at 29 cM.
Suggestive linkage to limb length was detected at 33 cM on mouse Chromosome 17 near D17Mit7 (LOD=2.92) with M16i-derived alleles conferring increased femur, humerus, tibia, and ulna lengths. In female animals, M16i-derived alleles confer decreased femur, tibia, and ulna lengths at this locus.
On mouse Chromosome 18, linkage to organ weight mapped to 73 cM (Orgwq9) near D18Nds1 (LOD=10.31). The QTL range of Orgwq9 spans 63 cM (D18Mit51) - 73 cM (D18Nds1). M16i-derived alleles confer increased heart and kidney weights at Orgwq9. Linkage to limb length mapped to 51 cM (Lmblgq6) near D18Mit51 (LOD=5.13). The QTL range of Lmblgq6 spans 33 cM - 69 cM. M16i-derived alleles confer increased femur, tibia, humerus, and ulna lengths at Lmblgq6.
Suggestive linkage to organ weight and limb length mapped to 4 cM (LOD=2.36 near D19Mit29) and 64 cM (LOD=2.16 near D19Mit6) on mouse Chromosome 19, respectively. M16i-derived alleles confer increased spleen weight at 4 cM, and confer increased tibia and ulna lengths at 64 cM.
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