The present invention provides a replication competent hepatitis C virus that
includes a heterologous polynucleotide. The invention also includes methods for
modifying a hepatitis C virus polynucleotide, selecting a replication competent
hepatitis C virus polynucleotide, detecting a replication competent hepatitis C
virus polynucleotide, and identifying a compound that inhibits replication of a
hepatitis C virus polynucleotide.