Deoxyribonucleic acid was extracted

Deoxyribonucleic acid was extracted by
standard methods with a phenol–chloroform–isoamyl alcohol mixture
(25:24:1), and then precipitated with isopropanol, washed
with ethanol, and dried under vacuum. The DNA pellet was dissolved
in 30 l of sterile distilled water and stored at −20 ◦C until
further use.