True and false positive peaks in genomewide scans: The long and the short of it

P Visscher, C Haley

Research output: Contribution to journalArticlepeer-review


When performing a genome scan in linkage or linkage disequilibrium studies to detect loci underlying complex or quantitative traits, it is important to attempt to distinguish between true and false positives using the appropriate statistical methods. There has been some controversy in the literature regarding the use of the length of a positive peak, i.e., the length of a chromosome region displaying identity-by-descent in linkage studies among affected individuals or the length of a continuous chromosome region for which the test statistic is above a certain threshold. We show in this study, by reasoning and by simulation studies, that conditional on the strength of evidence for a locus affecting a trait of interest, i.e., conditional on the peak height of a test statistic, there is no information in the length of the peak. Our finding has implications for linkage and association studies.
Original languageEnglish
Pages (from-to)409-14
Number of pages6
JournalGenetic Epidemiology
Issue number4
Publication statusPublished - May 2001


  • Analysis of Variance
  • Chromosome Mapping
  • False Positive Reactions
  • Genetic Linkage
  • Genome, Human
  • Humans
  • Linkage Disequilibrium
  • Regression Analysis


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