I am attempting to extract DNA from roots infected with a pathogen (so I want DNA from both the host and pathogen). I followed the Qiagen mini kit and checked the DNA quality of the DNA extracted with Nanodrop.
My 260/280 ratios are really nice, 2.0-2.2.
My 260/230 is negative, -0.1 to -11.
Concentrations range 8 to 15 ng/uL
I attempted a DNA extraction from some pathogen isolated and cleaned spores using the Qiagen maxi kit. I got similar results, good 280 ratio, negative 230 ratio, 9 ng/uL.
I believe the Nanodrop is working fine because my colleague got perfect Nanodrop results for an RNA extraction I assisted him in. We have no idea what the negative ratio could mean.