Figure 1.

Amplified PCR fragments from isolates expressing a unique SARS-CoV-2 Delta variant sequence, Poland, 17 July–11 August 2021 (n = 14)

SARS-CoV-2: severe acute respiratory syndrome coronavirus 2.

PCR was performed with (A) ARTICv3 primers (90_Left, 93_Right) [4,5] and (B) Midnight primers (27_Left, 28_Right) [3] and analysed with agarose gel electrophoresis. Isolates with unique SARS-CoV-2 Delta variant sequences (lanes 2–15) reveal a band at ca 500 bp (A) and at ca 1400 bp (B) rather than the expected size of 1,328 bp (lane 16, A) or 2,265 bp (lane 16, B). Lane 1: GeneRuler DNA ladder mix (Thermo Fisher Scientific); Lane 2: sample hCoV-19/Poland/PL_P3804/2021; Lane 3: sample hCoV-19/Poland/PL_P3711/2021; Lane 4: sample hCoV-19/Poland/PL_P3699/2021; Lane 5: sample hCoV-19/Poland/PL_P3705/2021; Lane 6: sample hCoV-19/Poland/PL_P3687/2021; Lane 7: sample hCoV-19/Poland/PL_P3686/2021; Lane 8: sample hCoV-19/Poland/PL_P3695/2021; Lane 9: sample hCoV-19/Poland/PL_P3696/2021; Lane 10: sample hCoV-19/Poland/PL_P3688/2021; Lane 11: sample hCoV-19/Poland/PL_P3693/2021; Lane 12: sample hCoV-19/Poland/PL_P3704/2021; Lane 13: sample hCoV-19/Poland/PL_P3794/2021; Lane 14: sample hCoV-19/Poland/PL_P3710/2021; Lane 15: sample hCoV-19/Poland/PL_P3709/2021; Lane 16: SARS-CoV-2 Delta AY.4 control sample, hCoV-19/Poland/PL_P3707/2021; Lane 17: negative control.