THE POSSIBLE TRIANGLE TEST FOR EXTREME DISCORDANT SIB PAIRS

For the analysis of quantitative traits in nuclear families, extreme d iscordant sib pairs proved to be more powerful than unselected sib pai rs. Here, we present a test that makes use of selected pairs and, in a ddition, restricts the parameters of the identical-by-descent distribu tion analogously to the ''possible triangle'' for affected sib pairs. In the Problem 2A data, extreme discordant sib pairs are selected. The analysis allowed the detection of most simulated major genes. (C) 199 7 Wiley-Liss, Inc.