Comparison of two linkage inference procedures for genes related to the P300 component of the event related potential

Our goal was to detect genes contributing to the P300 component of the event related potential (ERP). We found that all of the ERP traits were highly correlated. Most of them distinguished alcoholics from nonalcoholics. To have one summary variable for the ERP traits, we calculated the first principal component (PRIN1). After adjusting for age and sex, we screened for linkage of PRIN1 to all of the markers using the two-point Haseman-Elston sib-pair test. We compared results obtained from computing a moving average of two-point p-values ("regional" inference) in an approximately 10 cM region with those obtained from single, two-point tests. Different "suggestive" and "significant" linkage regions were found using the two methods. Based on the regional method, areas on chromosomes 2 and 5 should be followed up in future studies.