Posted 18 February 2009 - 03:24 PM
how much material are working with? (Might it be possible that the reason you see nothing is because the quantity of DNA extracted is too low to detect by gel)
And what type of tissue is the DNA extracted from? Is there trouble homogenising the tissue? (Might it be possible that DNA fails to extract because it is retained in the tissue)
And when you say "agarose gel electrophoresis produces no band", is it an empty, clear, spotless gel. Or do you see a smear? Could the DNA be degrading.
Does your phenol/chloroform DNA extraction protocol use protenase? If so how long do you incubate at 55C? Over exposure to 55C will fragment the genomic DNA. Depending on use, this can be acceptable.
Could there be a mistake when making buffers? Do the buffer contain enough EDTA? Right pH. Has the phenol been equilibrated to pH 8?
May your PCR products be long, your protocols short and your boss on holiday