highly mutable region hyper-variable loci HVR2 hypervariable region hypervariable hyper-variable loci HVR test hyper-variable loci Hypervariable Regions in Genes highly mutable region HVR 1 Hypervariable Region 1 HVR I y II hyper-variable region 1 HVR test HVRI and HVRII sequences Hypervariable region English hypervariable regions