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Phenotypic variation and identification of quantitative trait loci for traits influencing energy balance in mice
Abstract
Genetic regulation of energy balance is important to studies of human obesity and maintenance energy requirements of livestock. The regulation of heat loss (HLOSS; kcal/kg$\sp{75}$/d), measured by direct calorimetry as an indicator of energy expenditure in mice, has a significant genetic component. Objectives of this dissertation were to: (1) describe phenotypic variation for HLOSS and other traits relating to energy balance among inbred lines of mice and lines that had undergone selection for high (MH) and low (ML) HLOSS, and (2) identify quantitative trait loci (QTL) responsible for that variation. Mice representing three inbred lines, MH, ML, and their selected contemporaries were evaluated. MH had greater feed intake and HLOSS, but less body fat than ML mice. The greatest difference in HLOSS between a selection and inbred line was found between MH and the inbred line C57BL/6J (BL). Resource populations (n = 560) were made from crosses between MH and BL (HB population) and MH and ML (LH population) for the purpose of identifying QTL. Selective genotyping was used to complete a genome scan for QTL influencing HLOSS in the HB population. Eight chromosomes with preliminary evidence of QTL were evaluated using 40 microsatellite markers genotyped in the complete HB population. Interval analysis revealed significant evidence for QTL influencing HLOSS on Chromosomes 1, 2, 3 and 7 (HL1, HL2, HL3 and HL7, respectively), percent gonadal fat on Chromosome 1, and percent brown fat on Chromosomes 1 and 3. Only chromosomes 1 and 3 were evaluated in the LH population because HL1 and HL3 had the largest effects on HLOSS in the HB population. The presence of HL1, but not HL3, was confirmed in the LH population. The QTL identified in this study represent regions of the mouse genome containing genes important in the regulation of energy balance. Further investigation of these regions may lead to novel genes and pathways important to understanding the regulation of human obesity and energy requirements in livestock.
Subject Area
Genetics
Recommended Citation
Moody, Diane Ellen, "Phenotypic variation and identification of quantitative trait loci for traits influencing energy balance in mice" (1998). ETD collection for University of Nebraska-Lincoln. AAI9902968.
https://digitalcommons.unl.edu/dissertations/AAI9902968