RFLP analysis of 353-bp PCR products from 3 SH(−) (lanes 2, 3, and 4) and one SH(+) (lane 5) phenotyped individuals using SfaN I endonuclease and 2% Separide gel stained with ethidium bromide. DNA size standards (PhiX174 RF DNA.HaeIII) are shown in lane 1.