Researchers have shown that high dilutions of several bacterial and viral samples show a distinct electromagnetic signature. The team, headed by a Nobel Prize winning virologist, used aqueous solutions that were agitated and serially diluted i.e. according to homoeopathic techniques. The resulting signature remained even after the remaining DNA fragments were destroyed by chemical agents but it was destroyed by heating or freezing the sample.
Reference
Montagnier L, Aissa J, Ferris S, Montagnier J-L, Lavallee C (2009). Electromagnetic Signals Are Produced by Aqueous Nanostructures Derived from Bacterial DNA Sequences. Interdisciplinary Sciences: Computational Life Sciences, 1: 81-90.
[the full text of this paper can be downloaded here]