Synthetic DNA "adapters" are attached to the ends of the fragments, allowing them to bind to the sequencing platform.
All work must be done in a dedicated "Clean Lab" with HEPA filtration, positive air pressure, and UV sterilization. Researchers wear full-body suits to prevent shedding their own DNA onto the samples.
A distribution of very short fragment lengths suggests the DNA is genuinely old rather than modern contamination. Conclusion Ancient DNA: Methods and Protocols
Over time, DNA strands break into very short fragments, typically between 30 and 100 base pairs.
To handle chemical damage, researchers may use Uracil-DNA-Glycosylase (UDG) to remove uracil bases, reducing sequencing errors, though this can sometimes shorten already tiny fragments. Synthetic DNA "adapters" are attached to the ends
Software checks for high rates of C-to-T transitions at the ends of DNA fragments. If these "nicks" are present, it’s a signature of authenticity.
Proteinase K is added to break down cellular proteins and nucleases. A distribution of very short fragment lengths suggests
Samples are ground into a fine powder and soaked in EDTA, which chelates calcium and dissolves the bone matrix.