Yes, dentin contains DNA, but the amount is variable.
Dentin's DNA Content: A Detailed Look
Dentin, the hard tissue beneath the enamel of teeth, can indeed contain DNA. However, the amount present is not consistent. Studies have shown a variable range, with some samples exhibiting a high percentage of DNA (up to 70%), while others have significantly less. This variability can be attributed to several factors, including the individual's health, the age of the tooth, and postmortem conditions.
Several research papers support the presence of DNA in dentin. For instance, one study found that the average DNA content in dentin was 13.70 ± 18.62%, with a range from 0.003% to 70.14%. Interestingly, a portion of the DNA in some dentin samples (15.21%) originated from oral bacteria, possibly introduced after death. (https://pubmed.ncbi.nlm.nih.gov/29959351/)
The type of DNA found in dentin can vary. It can include:
- Endogenous Human DNA: This is the host's own DNA. The preservation of this DNA within the dentin matrix is relatively good, compared to other skeletal remains.
- Microbial DNA: Bacteria present in the oral cavity can contribute to the DNA found within dentin. This is more likely to be found in samples where postmortem contamination occurred. (https://www.nature.com/articles/s41598-018-28091-9)
While the dental pulp (the soft tissue inside the tooth) is often considered the primary source of DNA for forensic purposes, dentin can be a valuable alternative, especially in cases where the pulp is damaged or degraded. Decalcification might affect the DNA extraction, but it remains possible to obtain genetic material from dentin even after this process. (https://jada.ada.org/article/S0002-8177(14)60638-3/pdf)
The presence of specific genes related to dentin formation, such as DMP1 (dentin matrix acidic phosphoprotein 1), further supports the notion of DNA within this tooth tissue. (https://www.ncbi.nlm.nih.gov/gene/1758)
Conclusion
Dentin's DNA content is a key consideration for forensic science and genetic research. While not always abundant, the presence of both human and microbial DNA within dentin highlights its utility as a source of genetic material.
