Discontinuous Synthesis of DNA
on Lagging Strand
Molecular Diagnostics
(MDx) Review 537
Nucleotide position 1 2 3 4 5 6 7 8
Template DNA 5’ A G C T T G A C 3’
¬polymerase ¬polymerase
first pass second passDaughter DNA 3’ T C G A A C T G 5’
5’–3’ DNA template is read in 3’ to 5’ direction. DNA daughter strand is synthesized in 5’ to 3’ direction.
First pass: polymerase reads positions 4 to 1 on template—TCGA, assembles AGCT on daughter strand.
Second pass: polymerase reads positions 8 to 5 on template—CAGT, assembles GTCA on daughter strand.