Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học thế giới đề tài: Identification and reciprocal introgression of a QTL affecting body mass in mice | Genet. Sel. Evol. 36 2004 577-591 INRA EDP Sciences 2004 DOI gse 2004018 577 Original article Identification and reciprocal introgression of a QTL affecting body mass in mice Julian K. CHRISTIANSa Kellie A. RANCEa b Sara A. KNOTTa Pat M. PlGNATELLIa c Fiona OLIVERa Lutz BỪNGERa d a Institute of Cell Animal and Population Biology University of Edinburgh Ashworth Laboratories King s Buildings West Mains Road Edinburgh EH9 3JT UK Received 12 January 2004 accepted 27 April 2004 Abstract - 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 back-crossing. 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 . 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 loci introgression epistasis body mass 1. INTRODUCTION Many traits of medical agricultural or evolutionary importance vary continuously rather than discreetly and numerous studies have identified Corresponding author Present addresses b .
