Fig. 1

Construction of a congenic mouse strain carrying the obesity QTL on chromosome 6, named tabw2, derived from TALLYHO/JngJ (TH) mice in the C57BL/6J (B6) background by marker assisted backcrossing. An obese TH male mouse was crossed to a normal B6 female mouse, and the resultant F1 (or N1) mice were backcrossed to B6. Heterozygotes for the QTL were selected using flanking markers (shown as dotted line) and backcrossed again to B6. This procedure was repeated for 10 cycles of backcrossing at which point two heterozygotes were intercrossed to yield offspring that are homozygous for the TH alleles (tabw2 mice) and for the B6 alleles (control mice) across the congenic region