Our next batch of extractions went through the lab last week, and we found useable DNA in 17 of our 24 samples. They ranged in age from mid 1800s to 2017 - and some of our results were surprising. We expect any older sample to have somewhat degraded DNA, just by virtue of its age. But we found some newer samples with a higher level of degradation, and some older ones that were relatively “pristine”.
It’s difficult to account for the manner in which samples have been stored prior to getting to us - but experts say if the sample has been stored in optimum conditions (dry, no sunlight), the DNA should be relatively stable, regardless of age. For example, one sample from 1941 had a very low degradation index with a useable amount of DNA - another from the same year had minuscule amounts of DNA found and a very high degradation index. DNA was found under the back flap in both of these samples.
We will run all these samples through a second extraction process - in some cases looking for DNA in a different area to the original extraction - e.g. under the stamp, rather than the flap.
As we test more and more samples, we are interested to see if some sort of pattern emerges - the age of the envelope, the area sampled, versus the amount of DNA found. But for now, we don’t really know until we process the sample in the lab how it will fare.
So send through a photo of anything you might like to test to info@totheletterDNA.com - we’ll give it a visual inspection to make sure nothing precludes it from testing (e.g. obvious moisture stains) and do our best to find that DNA!