Comparing Three DNA Extraction Procedures for Cost, Efficiency, and DNA Yield

Abstract

An efficient deoxyribonucleic acid (DNA) extraction procedure that yields large quantities of DNA would provide adequate DNA for a large number of different analytical procedures. This study was conducted to compare three DNA extraction procedures for cost, time efficiency, and DNA content while extracting DNA from Kentucky bluegrass (Poa pratensis L.). Three students at the Univ. of Illinois with varying levels of DNA extraction experience conducted DNA extractions using Plant DNeasy™ Mini Kits, Plant DNAzol® Reagent, and a PEX/CTAB buffer. Costs varied significantly with cost (US$) per DNA sample of $3.04 for the DNeasy™ method, $0.99 for the DNAzol® method, and $0.39 for the PEX/CTAB extraction. The DNAzol® method was the fastest; although extracting 2.8 ng less DNA than the DNeasy™ method, it did not require the use of hazardous organic solvents, and random amplified polymorphic DNA (RAPD) markers were satisfactory for DNA fingerprinting of Kentucky bluegrass cultivars. The PEX/CTAB method, which did not include a tissue homogenization step, did not have reproducible banding patterns due to miniscule and inconsistent quantities of DNA extracted, or possibly due to inadequate purification. The investigator with the least DNA extraction experience was the slowest, while extracting 75% more DNA. All three methods are easily adapted to laboratories having personnel with different levels of experience. The DNAzol® Reagent method should save time and money, with reproducible results when many individual plant samples need to be identified. Chemical names used: potassium ethyl xanthogenate (PEX); cetyltrimethyl ammonium bromide (CTAB)