Determination of b-Actin-RNA/DNA Levels
To assess whether there was a decrease in the RNA amount relative to genomic
DNA content in triploids, we have conducted PCR experiments for
the single-copy b-actin gene, with DNA and cDNA samples from liver of
three diploid S. pyrenaicus and two triploid S. alburnoides as templates. Genomic
DNA and total RNA were extracted simultaneously from each sample
with the AllPrep DNA/RNA Mini Kit (QIAGEN). Amplification of DNA and
cDNA templates was conducted with b-actin primers (Table S3). PCR conditions
were as follows: preheating at 94C for 3 min, 30 cycles at 94C for
45 s, 60C for 40 s, and 72C for 3 min and a final extension at 72C for
15 min. Products were run in a 1.5% agarose gel and densitometrically
quantified with ImageG (Figure S2).