The A260/A280 ratio of the cDNA is measured to be ~1.8 using Beckman Coulter DU 800spectrophotometer. The cDNA is performance-tested in a control polymerase chain reaction (PCR) using primers of beta-actin. Gel electrophoresis analysis of the PCR products is performed in 1% (w/v) agarose gel with GeneRulerTM 1kb Plus DNA Ladder, one major band of around 400 bp can be observed.