The reaction mixture contains three of the complementary deoxynucleoside triphosphates, one of which is labeled with {HEAD ~ an isotope} such as tritium or α 32 P. The deoxynucleotide substrate that is omitted corresponds to {TAIL ~ the base} that is modified in the analog 
The reaction mixture contains three of the complementary deoxynucleoside triphosphates , one of which is labeled with { HEAD ~ an isotope } such as tritium or α 32 P. The deoxynucleotide substrate that is omitted corresponds to { TAIL ~ the base } that is modified in the analog
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH