MAP-BASED QUANTITATIVE TRAIT LOCUS IDENTIFICATION

Poultry gene mappers chose microsatellites as the main source of genet ic markers for poultry genome mapping, similar to the marker type used for other farm animals, laboratory animals, and humans. Optimal strat egies for applying DNA markers in poultry populations are discussed, i ncluding the number of markers to be used, genome representation, popu lation structure, choice of markers, population size, statistical stri ngency for association between markers and quantitative trait loci (QT L), and biological verification of a linkage. It is shown that an effi cient strategy should be based on a combination of a low stringent sta tistical test for the existence of linkage between a marker and QTL an d an appropriate genetic test for the discrimination between true and false linkage. The source of the genetic variation to be used is discu ssed and, as an illustration, three types of resource populations are presented. The informativeness of different matings using various geno types of the parents are considered and it appears that selection of m arkers based on the heterozygosity of the sire is the most efficient m arker screening approach.