Localization of Genes Potentially Controlling Susceptibility to the Lethal Effects of Alzheimer’s Amyloid Precursor Protein in Transgenic Mice

Variation in the susceptibility to the lethal effects of Alzheimer's Amyloid Precursor Protein (APP) transgene exists among various mouse strains. Inbred FVB/N mice, expressing high levels of the transgene-encoded APP, die prior to 200 days, while inbred 129.Tg2576 mice carrying the transgene are far less susceptible. When the two strains are crossed, (FVB/Nxl29.Tg2576) FI mice survive, as does the 129.Tg2576 parent. Intercross and backcross offspring survived at rates of 60% and 35%, respectively, at 200 days signaling the presence of a polygenic trait. The goal of this study was to establish a linkage to genes affecting susceptibility to the APP transgene. The possible quantitative trait loci (QTL) were established using various genetic markers scattered throughout the genome. The presence of multiple QTLs is possible from the data obtained; however, an increased chance of type I errors (false positives) exists due to the large number of markers used for the genome scan.