Abstract:Objective Previous study showed that one of several quantitative trait loci (QTL) responsible for weight of spinal cord in mice located at D15Mit158 with an interval of 30 cM on chromosome 15. To identify related genes, fine mapping of QTL within this region was conducted in this study. Methods An advanced intercross line (AIL) from A/J C- 57 BL/6J (F4) mice was used for partial genome scanning. High-resolution microsatellite markers around D15Mit158 were used to genotype in the F4 mouse population representing phenotypic extremes. Linkage analysis was performed by software Map Manager QTX19. Results A peak LRS-value of 17.3 was identified around D15Mit107 (p =1.8 10 -4 ), its contribution to the variance was 24% with an interval of 3.2 cM, and the LOD score was 3.75. Another suggestive linkage site was found around D15Mit28, its LRS-valve was 7.6(p =0.02) and contribution to the variance was 13%. Conclusion The QTL region of D15Mit158 contained two QTLs actually after fine mapping. One major QTL was around D15Mit107 with an interval of 3.2 cm, and another suggestive QTL was around D15Mit28 with an interval of 5 cm.