International Mammalian Genome Society

The 15th International Mouse Genome Conference (2001)

Table of Contents * Complex Genetics * Developmental Genetics * Gene Annotation * Gene Discovery * Genome Sequencing * Functional Genomics * Mutagenesis * Presentations * Verne Chapman Memorial Lecture

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POSTER 54 - FINE MAPPING OF OBESITY QTL FROM LINES OF MICE DIVERGENTLY SELECTED ON FAT CONTENT

Mr Ioannis Stylianou
Roslin Institute
Roslin
Midlothian EH25 9PS
United Kingdom

Co-Authors: 1) Keightley PD, 1) Bünger L, 2) Clinton M, 2) MacKay P, 2) Bulfield G, 3) Horvat S
Institutions: 1)Institute of Cell, Animal and Population Biology, University of Edinburgh, 2)Roslin Institute, 3)Roslin Institute & University of Ljubljana, Biotechnical Faculty, Zootechnical Department

Four body fat quantitative trait loci (QTL) in mice have been previously identified with Fob3 on mouse chromosome 15 having the largest effect. Here we report on the introgression of Fob3 using marker-assisted backcrossing and on the current status of fine mapping of Fob3. The Fob3 region has been introgressed from a line selected for low body fat (L-Line) into a line derived from the same base population but selected for high body fat (F-line) to create a congenic line (Fchr15L). The effect of the introgressed QTL region covering a ~40cM region is female-specific. Single marker analysis of variance indicates up to a 25% difference in body fat between female mice from the F-line and those from the congenic Fchr15L line. Fine mapping of this 40cM region is under way. Crossing of congenic lines generated heterozygous F1 animals and recombinants have been collected in the F2 generation. The progeny of these recombinants are being phenotyped and genotyped with 15 polymorphic markers spanning the 40cM region to narrow down the target region further. Positional candidate genes will be selected from the mouse map or by comparative mapping from the human map and examined for differential expression between the Fchr15L, F and L-lines using microarray technology. This should help to identify a causal gene(s) for Fob3 that is responsible for the observed effect on obesity in females.