Project description:To characterize the genetic basis of hybrid male sterility in detail, we used a systems genetics approach, integrating mapping of gene expression traits with sterility phenotypes and QTL. We measured genome-wide testis expression in 305 male F2s from a cross between wild-derived inbred strains of M. musculus musculus and M. m. domesticus. We identified several thousand cis- and trans-acting QTL contributing to expression variation (eQTL). Many trans eQTL cluster into eleven ‘hotspots,’ seven of which co-localize with QTL for sterility phenotypes identified in the cross. The number and clustering of trans eQTL - but not cis eQTL - were substantially lower when mapping was restricted to a ‘fertile’ subset of mice, providing evidence that trans eQTL hotspots are related to sterility. Functional annotation of transcripts with eQTL provides insights into the biological processes disrupted by sterility loci and guides prioritization of candidate genes. Using a conditional mapping approach, we identified eQTL dependent on interactions between loci, revealing a complex system of epistasis. Our results illuminate established patterns, including the role of the X chromosome in hybrid sterility.
Project description:Mice were killed between 24 to 26 months of age, tissues removed, rapidly frozen on dry ice, and stored in liquid nitrogen. Total liver RNA was isolated from frozen tissue as described (T. Tsuchiya, J.M. Dhahbi, X. Cui, P.L. Mote, A. Bartke, S.R. Spindler, Physiological Genomics, Submitted). mRNA levels were measured using the Affymetrix mouse U74Av2 array according to standard protocols. After hybridization, arrays were scanned using a Hewlett-Packard GeneArray Scanner. Image analysis was performed as described (Cao SX, Dhahbi JM, Mote PL, and Spindler SR. Genomic profiling of short- and long-term caloric restriction effects in the liver of aging mice. Proc Natl Acad Sci U S A 98: 10630-10635, 2001). A more detailed description of the methods can be found in (T. Tsuchiya, J.M. Dhahbi, X. Cui, P.L. Mote, A. Bartke, S.R. Spindler, Physiological Genomics, Submitted). This SuperSeries is composed of the following subset Series: GSE1086: Dwarf Ad libitum; GSE1087: Dwarf Calorie Restricted; GSE1088: Normal Ad Libitum; GSE1089: Normal Calorie Restricted Experiment Overall Design: Refer to individual Series
