SIB PAIRS VERSUS PEDIGREES - WHAT ARE THE ADVANTAGES

Standard approaches to linkage mapping of complex traits such as diabe tes encompass two basic techniques or strategies: 1) tracing of cosegr egation and recombination phenomena between marker alleles and putativ e trait-influencing alleles among members of large pedigrees (i.e., pe digree analysis) and 2) assessing the number of marker alleles shared at a particular locus among pairs of relatives manifesting the same tr ait (sib pair or allele-sharing analysis). These techniques rely on di fferent assumptions and statistical models and thus are appropriate fo r different situations. In addition, Each technique possesses certain advantages and disadvantages: pedigree analysis is often assumption-la den but powerful, whereas allele-sharing methods require few assumptio ns but are not very powerful. In this review, we discuss the relative advantages and disadvantages of pedigree and allele sharing analyses, as well as the possible extensions of these techniques that might make them more flexible. Ultimately, however, we argue that hybrid statist ical models and methods that draw on aspects of each approach are like ly to be the analytic tool of the future for mapping genes that underl ie complex traits.