| Genetic and physical mapping of human and animal genomes has been greatly facilitated by the use of chromosome specific DNA libraries. Mapping with libraries specific to a chromosome or chromosomal region increases marker saturation by reducing the gaps resulting from a purely random shotgun approach. This study was undertaken to construct a genetic and physical map of microsatellites on the chicken Z chromosome. This chromosome is the fifth largest in the chicken genome, comprising about 8% of the total, yet very few microsatellites have been mapped to it. DNA originating from the chicken Z chromosome was previously isolated and reported. This was used to construct a small insert library in Lambda ZAP Express, representing 14 chromosome equivalents. This library was screened for microsatellites with an (AC)12 oligo, and positive clones were isolated. Confirmation of the presence of the microsatellite, as well as its approximate location in the insert was accomplished by PCR amplification. Clones with adequate flanking regions were sequenced, and primers for 19 microsatellites were developed.; These primers were used to genotype individuals from the East Lansing poultry reference population and a linkage map was constructed. Thirteen markers were scorable and polymorphic in the population. These were combined with 64 existing markers, and the resulting map spans 220 cM with an average spacing of 2.7 cM between markers. The physical location of selected markers were established by fluorescent in situ hybridization (FISH.) Hybridization results enabled the anchoring and orientation of the linkage group along the length of the Z chromosome. |
