Biological samples are first lysed and homogenized in the presence of a highly denaturing guanidine-thiocyanate–containing buffer, which immediately inactivates RNases to ensure intact RNA. Ethanol is added to provide appropriate binding conditions, and mixture is then applied to the first spin-column, where genomic DNA binds to the membrane, then add filtrate to the second spin-column, and total RNA binds to this membrane. Finally, contaminants are efficiently washed away separately. High-quality gDNA and total RNA are then eluted in 30-100 μl water from separate spin-column.