Hi everybody,
I am using the High Pure Viral Nucleic Acid Kit (Roche) for extraction genomic DNA from blood (buffy coat). The DNA concentration is quite good (50-100 ng/ul) and the A260/A280 ratio is 1.8 - 2.0. But when I check the result by electrophoresis, I see some samples have bands forming ladder (as the image attached). I have no idea what the reason is, any suggestions on this would be helpful! Thank you.