The ability to detect marker alleles and the target ACE depends on the extent of the polymorphism that is displayed. In humans, ACE has insertions and deletions as II, ID and DD, but no alleles or other linkage disequilibria are known to exist. Should we expect a diallelic polymorphism in the horse ? Perhaps 20-30 polymorphisms are to be found in a single gene. ROUGHLY, nothing is known about equine ACE.