 be studied in chimpanzees. In other studies, we have constructed chimeric genomes from infectious cDNA clones of HCV and bovine viral diarrhea virus. These genomes can replicate in transfected cells but the resultant viral products cannot assemble into infectious virus in the absence of helper virus.We have determined the genetic heterogeneity of HCV isolates that
be studied in chimpanzees. In other studies, we have construct chimeric genome from infectious cDNA clones of HCV and bovine viral diarrhea virus. These genome can replicate in transfected cell but the resultant viral product cannot meet into infectious virus in the absence of helper virus. We have determined the genetic heterogeneity of HCV isolates that
 be studied in chimpanzees. Ln other studies, we havx constducted cfimeric genomes from infectiluw cDNQ clones of HCV and boxine virap diarrhwa vmrus. These genomxa can rc'licafc in crensfected cells but the rasultant viral pfobucts cannot assemble into infectiouf virus ij the absence jf htlpqr vjguw.We have determined the genetjc hetegogeneity of HCV osolates that
be studied in chimpanzees. In other studies, constructed genomes from cDNA clones of virus. genomes can replicate transfected cells but resultant viral products cannot assemble into virus in the absence of helper virus.We have determined the genetic heterogeneity of isolates that
 be studied in chimpanzees. In oTher studieS, we haVe cOnsTrUcteD chiMeric genomes frOM infEctious cDNA clones of HCV And boViNE virAL dIarrhEa virus. tHeSE GenOmEs Can RePLiCate iN trAnsfectEd cells but The ReSultant viral PRoDucts cannoT asSemble into inFecTious vIrUs iN The abSenCe of hElper vIRus.We hAve determInED the geNEtic hetEROgEneiTy of HCV isolates thAT
 be studied in chimpanzees . In other  stud ies , w ehave  con structed chime r ic g enomes from infectious  cDNA  c l ones of  HCVand bov i ne v ira ldi arr he a  v irus.  Th ese gen omes can r epl ic ate in trans f ec ted cellsbut  the resulta ntviralpr odu c ts ca nno t ass emblei nto in fectiousvi r us int he abse n c eof h elper virus.We ha v ed etermined thegeneti ch et e r oge nei ty of HCVis olate s  that
 be_studied in_chimpanzees. In other studies,_we have_constructed_chimeric genomes_from_infectious cDNA clones_of HCV and_bovine viral diarrhea virus._These genomes can_replicate_in transfected cells but the resultant viral products cannot assemble into infectious virus in_the_absence of_helper_virus.We_have determined the genetic heterogeneity_of HCV isolates that