Cremation reduces human remains to what are commonly called “ashes,” but these are not true ash, but pulverized bone fragments. While the process significantly alters biological material, it is indeed possible to attempt DNA testing on these cremated remains, though the feasibility and reliability are influenced by several factors.
What Happens to DNA During Cremation?
Cremation involves subjecting a body to extreme temperatures, typically ranging from 1,400 to 1,800 degrees Fahrenheit (760 to 982 degrees Celsius). This intense heat causes a process called thermal denaturation, where the double-helix structure of DNA unwinds and breaks apart. The hydrogen bonds holding the DNA strands together are destroyed, leading to fragmentation of the molecule.
Most organic materials within the body, including soft tissues, are consumed during this process, turning into vapor. However, bones, which are largely composed of inorganic calcium phosphates, are more resilient to heat. They become brittle fragments, which are then processed into a fine powder.
Is DNA Extraction from Ashes Possible?
Extracting DNA from cremated remains is possible, yet it presents significant challenges due to the extensive degradation caused by high temperatures. Successful extraction primarily relies on the presence of bone fragments, as these are the most likely to retain any genetic material.
Laboratories often focus on mitochondrial DNA (mtDNA) rather than nuclear DNA (nDNA) when testing cremated remains. Mitochondrial DNA is found in thousands of copies per cell, making it more abundant than nuclear DNA, which is present in only two copies. This higher copy number contributes to mtDNA’s greater resistance to degradation compared to nuclear DNA. Since mtDNA is inherited solely from the mother, it can confirm maternal lineage, but it provides less detailed genetic information than nuclear DNA.
Several factors influence the success rate of DNA extraction from cremains. These include the specific temperature reached during cremation, the duration of the process, and the presence of larger bone fragments or teeth. Less complete cremation or the existence of sheltered bone fragments may yield better results. Advanced laboratory techniques are employed to attempt to piece together the degraded DNA fragments, but success is not guaranteed, and the amount of usable genetic information can be limited. Contamination from external sources can also complicate the analysis.
Why Test Ashes and What are the Alternatives?
DNA testing ashes can serve various purposes. Confirming identity is a common motivation, such as in cases of disaster victim identification or if there are concerns about a mix-up of remains. Some also seek DNA from ashes for genealogical research to trace family history or for legal purposes, including resolving paternity or maternity disputes and inheritance claims. Additionally, some families wish to preserve a tangible piece of a loved one for future generations.
When DNA testing is desired, obtaining samples before cremation offers significantly better chances of success. Biological samples like hair, blood, and tissue collected prior to the cremation process contain intact DNA that is much easier to analyze. Other viable alternatives include personal items such as nail clippings, used toothbrushes, or dried blood on fabric. If direct samples are unavailable, relationship testing with living biological relatives can also provide genetic insights. These pre-cremation and alternative samples are generally more reliable for comprehensive DNA analysis.