Scheme of vector layouts representing different prothrombin haplotypes. The original SV40 poly-A site cassette was removed from the vector and replaced in its entirety by the prothrombin gene polyadenylation signal, cleavage site, and 3′ flanking region. Vectors of the “short” type are identical to their parent plasmids except for a shortened 3′ flanking region. SV40 Prom. indicates SV40 promoter.