Figure 1: Gel electrophoresis of polymerase chain reaction product. Number 1 is a negative control of PCR, number 2 is 100 bp DNA size marker, and numbers 3, 4, 5, and 6 are HTLV1 positive samples which showed 222 bp and 149 bp fragments of HTLV1 LTR and human TATA-binding protein (internal control of PCR) genes, respectively.