Incorporating larger families in identity-by-descent based linkage analysis

Genome scans for alcoholism susceptibility genes were carried out using identity-by-descent-based statistics for qualitative traits. We compared the results when 1) multipoint information was used for all families, where some had to be truncated, 2) multipoint information was used only for small families while large (untruncated) pedigrees were analyzed with a single-point approach, and 3) single-point analysis was used for all pedigrees. Differences between the methods were observed, but neither method could identify regions related to the susceptibility for alcoholism.