A synteny map of the horse genome comprised of 240 microsatellite and RAPDmarkers

To generate a domestic horse genome map we integrated synteny information f or markers screened on a somatic cell hybrid (SCH) panel with published inf ormation for markers physically assigned to chromosomes. The mouse-horse SC H panel was established by fusing pSV2neo transformed primary horse fibrobl asts to either RAG or LMTk(-)mouse cells, followed by G418 antibiotic selec tion. For each of the 108 cell lines of the panel, we defined the presence or absence of 240 genetic markers by PCR, including 58 random amplified pol ymorphic DNA (RAPD) markers and 182 microsatellites, Thirty-three syntenic groups were defined, comprised of two to 26 markers with correlation coeffi cient (r) values ranging from 0.70 to 1.0. Based on significant correlation values with physically mapped microsatellite (type II) or gene (type I) ma rkers, 22 syntenic groups were assigned to horse chromosomes (1, 2, 3, 4, 6 , 9, 10, 11, 12, 13, 15, 18, 19, 20, 21, 22, 23, 24, 26, 30, X and Y). The other 11 syntenic groups were provisionally assigned to the remaining chrom osomes based on information provided by heterologous species painting probe s and work in progress with type I markers.