Two-dimensional gels used for the selection of differential spots. The proteomic approach shown compares the protein profile of a sample containing neoblast cells with one in which these cells have been depleted by irradiation. Upper panels show a comparison between two silver-stained 2D gels of a whole proteome from wild type and irradiated animals. Spots not present in the proteome of irradiated planarians are shown and lettered in red. These spots were selected and analyzed by mass spectrometry. Bottom panels show DIGE comparison of irradiated and wild type planarian proteomes. Spots that increase or decrease in the irradiated planarian proteome are shown in red and blue, respectively. These spots were included in the mass spectrometry analyses.