Figure 1.

Diagrammatic representation of granulocytes in separation medium evaluated for DNA extraction in this study. After centrifugation of diluted whole blood over-layed on Ficoll medium, usually plasma (layer 1) and white blood cells (layer 2) are recovered for further studies. The residual whole blood containing ficoll solution (layer 3) and erythrocytes/granulocytes (layer 4), which is often discarded, was evaluated in this study as a rich source of high quality DNA without further purifications of cells from separation medium.