Detection of DNA in ancient bones using histochemical methods.

The research explores techniques for detecting DNA within the structural holes (osteocytic lacunae) found in ancient bones. In particular, the study focus on fragments of human and horse bones from historical Pompeii, testing various stains and analysis methods to efficiently and cost effectively identify DNA in these samples.

Study Subject and Methodology

• The selected bones for examination were fragments from two human individuals discovered in the Pompeian house of C. I. Polybius and metacarpals from two horses, found in the “Casti Amanti” house in Pompeii. Both these ancient structures were buried during the 79 A. D. eruption of Mount Vesuvius.
• For control comparison, the researchers also studied fragments of femurs from a modern horse, a modern swine and a modern amphibian.

Histochemical Applications

• The researchers used various histochemical techniques in order to stain the DNA for improved visibility. Some of the sections from bone samples were stained with DNA-specific fluorochromes, namely 4′-‘6-diamidino-2-phenylindole (DAPI) and chromomycin A3 (CMA).
• Other bone sections were stained with a classic genetic staining method called the Feulgen reaction which is highly specific to DNA. All of these staining methods provided a positive reaction for the presence of DNA within the osteocytic lacunae.

Histological Analysis

• The researchers compared these results with a histological analysis, performing this analysis on undecalcified, finely ground and unstained sections of the bones. The results of the histological analysis were in agreement with the results from the stained samples using both fluorochromes or the Feulgen reaction.
• Bones that showed good structural morphology (histology) were also positive for DNA presence when stained with the aforementioned techniques. This suggests a good correlation between the bone’s histological condition and the feasibility to retrieve DNA.

Research Significance

• The findings of this study imply that employing traditional DNA-specific histochemical techniques combined with histological analysis can be an effective strategy when studying DNA extracted from ancient bone remains.
• This approach additionally promises to reduce both time and cost, hence improving the efficiency of archaeological and paleontological research involving DNA extraction and analysis from ancient remains.