Ten polymorphic microsatellite markers mainly of the poly (TG) type were examined on the two international reference families, the East Lansing reference family and the Compton reference family. Three of the markers were polymorphic on the East Lansing family (linkage groups E), three on the Compton family (linkage groups C), and four were polymorphic on both families. The microsatellite markers were well dispersed among the various linkage groups, and there was no evidence for clustering of the markers within the map. Common microsatellite markers were able to associate linkage groups from the two genetic maps. Association of linkage groups E2 with C4, E10 with C13, and E1 with C15 are found. Linkage group E1 is located on chromosome 1, and because of the association between E1 and C15, C15 is therefore assigned to chromosome 1. A newly defined linkage group (E20) was found in case of microsatellite marker MCW14. The relative distances between markers and the gene order of the markers can change upon addition of more markers to the linkage maps.