Although the ability of endotoxin to stimulate inflammatory responses is well known, the molecular mechanisms of the pathways that mediate this inflammation and those that regulate it remain undiscovered. To identify novel genes associated with the response to endotoxin, the Immunogenetics Group carried out positional cloning studies using mouse strains that have high or low responses to endotoxin. The group determined three different loci using this approach and is currently using DNA sequence comparison, gene expression studies and small interfering RNA (siRNA) to identify the genes that underlie these quantitative trait loci (QTL). In addition, Cook's group is using similar approaches to identify QTL related to the allergic immune responses.