FUNCTIONAL GENES MAPPED ON THE CHICKEN GENOME

Microsatellite polymorphisms are finding increasing use in genetics. I n addition to the random isolation of microsatellite markers, such mar kers can also be developed from sequences already present in public do main databases. An advantage of public domain databases is that these microsatellites are known to be located within or close to identified functional genes, In this study the GenBank and EMBL databases were sc reened for microsatellite markers and primers were defined for amplifi cation. Subsequently, these markers were tested on a panel of five dif ferent birds from layer and broiler stocks and on the international re ference families: the East Lansing reference family and the Compton re ference family. Of the 33 loci tested, 25 were polymorphic on the test panel and from these 25, 14 were polymorphic in one or both reference families. Twelve of the 14 loci that could be mapped fell into previo usly defined linkage groups. The other two markers were not linked, Be cause three of the loci had previously been mapped to specific chromos omes by in situ hybridization, linkage groups E6 and C3 could be assig ned to chromosome 6, E5 and C17 to chromosome 4 and E21 to one of the microchromosomes.