Yes, bones contain DNA, but the presence and quality of the DNA depend on several factors. While bone itself is largely mineralized, the cells within the bone, particularly in the less mineralized spongy bone, contain DNA. However, the DNA degrades over time and with exposure to environmental factors.
Factors Affecting DNA Preservation in Bones
- Time: The older the bone, the less DNA it typically contains due to degradation.
- Environmental Conditions: Exposure to heat, moisture, and microorganisms can significantly affect DNA preservation. For example, researchers can extract usable DNA from bones subjected to temperatures between 200 and 250 degrees centigrade, but there’s a steep drop-off in DNA concentration between 350 and 550 degrees centigrade.
- Bone Type: Different types of bone may yield varying amounts of DNA. Studies have explored the relationship between bone type and DNA yield, aiming to optimize sampling strategies.
- Preservation: Intact bones preserved in good conditions are more likely to yield usable DNA than fragmented or poorly preserved bones. Fossilised bone, where minerals have replaced the original organic material, generally lacks recoverable DNA.
DNA Extraction from Bones
Forensic laboratories routinely extract and analyze DNA from bones, particularly intact large bones preserved well. Techniques used for extracting ancient DNA from sources like woolly mammoths are also applicable to human remains. The amount of DNA recoverable varies greatly depending on the factors above. In some cases, only nanograms of DNA may be present per gram of bone tissue.
Examples of DNA Extraction from Bones
- Forensic Investigations: DNA from bones is crucial in identifying victims of crimes or disasters, especially in cases involving badly burned or decomposed remains.
- Ancient DNA Studies: Analysis of DNA extracted from ancient human remains helps researchers understand human evolution and migration patterns.
