Detection of DNA in ancient bones using histochemical methods

We describe histochemical techniques for detecting DNA within the osteocyti c lacunae of ancient bones. The bones examined were fragments of femurs fro m, two human individuals found in the Pompeian C. I. Polybius house and fra gments of metacarpals from two horses (Equus sp.) found in the Pompeian "Ca sti Amanti" house. Both buildings were buried by the 79 A. D. Vesuvius erup tion. Fragments of femurs from a modern horse, a modern swine and a modern amphibian also were studied as controls. Some bone sections were stained wi th two different DNA-specific fluorochromes, 4'-'6-diamidimo-2-phenylindole (DAPI) and chromomycin A3 (CMA), while others were stained by the Feulgen reaction. All of the techniques gave a positive reaction within the osteocy tic lacunae. Histological analysis of the undecalcified, ground and unstain ed sections agreed well with results of bone sections stained with either t he fluorochromes or the Feulgen reaction. Bones showing good histology also were positive by our DNA-specific stain. Histochemical and histological an alyses correlated well with the success of DNA extraction and amplification . Using conventional DNA-specific histochemical techniques in conjunction w ith histological analysis can be useful in the study of DNA extracted from ancient bone remains while reducing both the amount of time and cost.