Morphological and molecular analysis calls for a reappraisal of the red rain cells of Kerala.

Early studies on the coloured particles that fell as red rain over southern India identified them as unicellular eukaryotes such as members of the red algae or fungi; however, the results of the present investigation are not consistent with this designation. Using transmission electron microscopy, we have demonstrated significant differences in the ultrastructure when compared with representative species from these other groups. Most notably, the red rain cells show no evidence of typical eukaryotic internal structures such as mitochondria or endoplasmic reticulum.

DNA unmasked in the red rain cells of Kerala.

Extraordinary claims have been made for the biological properties of the red rain cells of Kerala, including a suggestion that they lack DNA. We have investigated the fluorescence properties of red rain cells, and the solubility of the red pigment in a variety of solvents. Extraction of the pigment with DMSO allowed successful demonstration of DNA using DAPI staining.