cDNA blotting offers an alternative method for gene expression studies

Northern analysis of bilberry fruit RNA using a non-radioactive detection system proved to be extremely difficult. To overcome this problem, we used cDNA instead of RNA for the blotting step. The RNA was translated to cDNA directly after isolation. The cDNA was then separated by electrophoresis, stained with ethidium bromide, and blotted onto a nylon membrane by Southern transfer. Non-radioactive detection by digoxigenin-dUTP was then possible. This method resolves several problems associated with northern blotting and is especially efficient when applied to recalcitrant plant material.