Power to detect QTL in a free-living polygynous population

Evolutionary biologists attempting to detect quantitative trait loci (QTL) in natural populations have thus far had to carry out some kind of cross wi th their study organism. Such techniques often increase the probability of detecting linkage, but are impossible or undesirable in many populations. A potential way of overcoming this problem is to carry out linkage studies i n large complex pedigrees. In this paper we contrast the power to detect li nkage in a complex pedigree of red deer (Cervus elaphus) with that of the w idely used half-sib design. When a QTL of magnitude 1 phenotypic standard d eviation is segregating and completely linked to a marker, the extended ped igree has power of 0.67, whereas the half-sib design has power of just 0.21 . We conclude that detecting QTL may be possible in intensively studied nat ural populations, provided detailed life history data and good pedigree inf ormation are available.