▁The ▁DNA ▁copies ▁concaten ate ▁head ▁to ▁tail ▁in ▁a ▁long ▁str and , ▁and ▁are ▁compact ed ▁into ▁a ▁DNA ▁nan ob all . ▁ ▁The ▁nan ob alls ▁are ▁then ▁ad s or bed ▁onto ▁a ▁sequ encing ▁flow ▁cell . ▁The ▁color ▁of ▁the ▁flu ores c ence ▁at ▁each ▁inter rog ated ▁position ▁is ▁recorded ▁through ▁a ▁high - resol ution ▁camera . ▁ ▁Bio in format ics ▁are ▁used ▁to ▁analyze ▁the ▁flu ores c ence ▁data ▁and ▁make ▁a ▁base ▁call , ▁and ▁for ▁mapping ▁or ▁quant ifying ▁the ▁ 5 0 bp , ▁ 1 0 0 bp , ▁or ▁ 1 5 0 bp ▁single - ▁or ▁pa ired - end ▁reads . ▁ ▁DNA ▁Is olation , ▁fragment ation , ▁and ▁size ▁capture ▁ ▁C ells ▁are ▁l ys ed ▁and ▁DNA ▁is ▁extracted ▁from ▁the ▁cell ▁l ys ate . ▁ ▁The ▁high - m ole cular - weight ▁DNA , ▁often ▁several ▁meg abase ▁pairs ▁long , ▁is ▁fragment ed ▁by ▁physical ▁or ▁en zym atic ▁methods ▁to ▁break ▁the ▁DNA ▁double - str ands ▁at ▁random ▁intervals . ▁ ▁Bio in form atic ▁mapping ▁of ▁the ▁sequ encing ▁reads ▁is ▁most ▁efficient ▁when ▁the ▁sample ▁DNA ▁contains ▁a ▁narrow ▁length ▁range . ▁For ▁small ▁R NA ▁sequ encing , ▁selection ▁of ▁the ▁ideal ▁fragment ▁lengths ▁for ▁sequ encing ▁is ▁performed ▁by ▁gel ▁elect roph ores is ; ▁for ▁sequ encing ▁of ▁larger ▁fragments , ▁DNA ▁fragments ▁are ▁separated ▁by ▁be ad