MicroRNAs are natural regulators of gene expression affecting almost every cellular process (growth and development cell differentiation cell death). They occur naturally in diverse animal and plant species and hundreds have been discovered since the late 1990s. A single miRNA can ramp down expression of multiple genes. Nucleic acids bind to the surface of the glass fiber fleece in the presence of a chaotropic salt (guanidine HCl). This allows the High Pure filter tube to specifically immobilize nucleic acids (both DNA and RNA) while they are freed of contaminants.Capacity The High Pure Spin filter Tubes hold up to 700 muL sample volume.