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Genetics Selection Evolution

Open Access

Identification and reciprocal introgression of a QTL affecting body mass in mice

  • Julian K Christians1Email author,
  • Kellie A Rance1, 2,
  • Sara A Knott1,
  • Pat M Pignatelli1, 3,
  • Fiona Oliver1 and
  • Lutz Bünger1, 4
Genetics Selection Evolution200436:577

Received: 12 January 2004

Accepted: 27 April 2004

Published: 15 September 2004


The aim of this study was to examine the effects of a QTL in different genetic backgrounds. A QTL affecting body mass on chromosome 6 was identified in an F2 cross between two lines of mice that have been divergently selected for this trait. The effect of the QTL on mass increased between 6 and 10 weeks of age and was not sex-specific. Body composition analysis showed effects on fat-free dry body mass and fat mass. To examine the effect of this QTL in different genetic backgrounds, the high body mass sixth chromosome was introgressed into the low body mass genetic background and vice versa by repeated marker-assisted backcrossing. After three generations of backcrossing, new F2 populations were established within each of the introgression lines by crossing individuals that were heterozygous across the sixth chromosome. The estimated additive effect of the QTL on 10-week body mass was similar in both genetic backgrounds and in the original F2 population (i.e., ~0.4 phenotypic standard deviations); no evidence of epistatic interaction with the genetic background was found. The 95% confidence interval for the location of the QTL was refined to a region of approximately 7 cM between D6Mit268 and D6Mit123.


quantitative trait lociintrogressionepistasisbody mass

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Authors’ Affiliations

Institute of Cell, Animal and Population Biology, University of Edinburgh, Ashworth Laboratories, Edinburgh, UK
Energy Balance and Obesity Division, Rowett Research Institute, Aberdeen Centre for Energy Regulation and Obesity (ACERO), Bucksburn, Aberdeen, UK
Liverpool School of Tropical Medicine, Liverpool, UK
Animal Breeding & Genetics Dept., Animal Biology Division, Scottish Agricultural College, Bush Estate, Penicuik, UK


© INRA, EDP Sciences 2004