PRELIMINARY LINKAGE MAP OF THE CHICKEN (GALLUS-DOMESTICUS) GENOME BASED ON MICROSATELLITE MARKERS - 77 NEW MARKERS MAPPED

Microsatellite polymorphisms are finding increasing use in genetics. T he objectives of this study were I) to enlarge the number of markers t o contribute to a well-defined linkage map oi: the chicken genome; and 2) to create a preliminary linkage map only based on microsatellite m arkers. The need for microsatellite markers is high for performing a w hole genome scan for the identification of quantitative trait loci. Se venty-seven newly developed microsatellite markers that were polymorph ic on either one or both of the reference populations were mapped and in combination with all previously described markers, used to construc t preliminary linkage map of the chicken genome. The 128 microsatellit e markers mapped thus far cover 23 of the 38 linkage groups of the Eas t Lansing reference population. In the case of the Compton reference p opulation, 20 linkage groups out of 40 are covered with microsatellite markers. No linkage was found in the East Lansing population with fiv e markers, and in the case of the Compton population four markers were unlinked. About 42 and 32% of the East Lansing and Compton maps, resp ectively, were covered by the 128 microsatellite markers. The microsat ellite markers are well dispersed among the various linkage groups and there was no evidence for clustering of the markers within the map Wi th the 38 markers that were mapped on both reference populations, 10 o f the East Lansing linkage groups could be associated with 13 of the C ompton linkage groups.