PARENTAGE TESTING AND LINKAGE ANALYSIS IN THE HORSE USING A SET OF HIGHLY POLYMORPHIC MICROSATELLITES

Ten (TG)(n) positive clones, isolated from an equine genomic library a nd sequenced, contained 12-19 uninterrupted TG repeats. Primers for po lymerase chain reaction (PCR) were synthesized and nine of these (TG)( n) loci (HTG7-15) were successfully amplified and utilized in this stu dy together with five previously reported equine microsatellite loci ( HTG2-6). The PCR products were analysed by polyacrylamide gel electrop horesis followed by automated laser fluorescence detection or autoradi ography. All microsatellites showed polymorphism and stable Mendelian inheritance. Differences in microsatellite variability between horse b reeds were detected. A linkage analysis comprising HTG2-15, one coat c olour gene and 16 genetic blood markers enabled addition of HTG2 to li nkage group U2 and a new linkage group (U6) was established comprising the loci HTG7 and HTG12. Close linkage was excluded within a set of e ight microsatellites. The estimated probability of exclusion in four b reeds for a parentage test based on these eight loci varied between 0. 96 and 0.99.