You usually see such impressive news like recovering human DNA from the fossils of a Neanderthal who has died about 70,000 years ago. This is huge and a record. Usually, human DNA does not last that long, but other types of DNAs belonging to other types of life forms can last a lot longer than that. We’re going to discuss this in the following. Life has a strange way of holding on, clinging to our world and always finding ways to evolve and pass on the already-accumulated knowledge. This knowledge is usually passed through DNA. So DNA is this “tough guy” who pushes evolution forward and it deserves us knowing more about it. So, let’s start with a simple question!
How long does DNA last?
DNA lasts for a little over 1,000 years. For example, scientists have extracted DNA from the leg bones of an extinct moa bird in New Zealand and thus found out that the half-life of a DNA is 521 years. According to scientists specialized in DNA extraction techniques, every 1000 years, about 75% of the genetic information in a deceased being is being erased by time and outside conditions. After another 6.8 million years there’s no sign of genetics remained, but that’s a lot, right?
Things get a little over the top with bacterial RNA. RNA is one of the constituents of any form of life, along with DNA and other lipids, proteins, and carbohydrates. Studies have shown that bacterial RNA can last up to 419 million years. Scientists have managed to extract bacterial RNA from ice crystals that were almost half a billion years old. Impressive, right? It’s like life just doesn’t want to die out without leaving its traces in the sand of time.
How long does DNA last in saliva?
DNA Saliva samples in tightly closed containers, at room temperature, usually maintain the integrity of DNA for at least 5 years.
All you need to know about DNA sampling methods
DNA sampling methods have evolved drastically over the last 20 years. This led to the identification of the Romanov royal family bodies or even the infamous outlaw Jesse James. Exhumed corpses do hold many secrets to us nowadays. Nevertheless, luck plays a major part in how the DNA is preserved. The Deoxyribonucleic acid is quite vulnerable to normal natural elements, such as sunlight, water or different kinds of enzymes that destroy it. So, scientists should also get lucky and do no get stricken with challenges such as “no confirmed relatives to find”, decayed bodies, damaged infrastructure.
Usually, the most important “gatekeepers” of the DNA are the bones and teeth. The skeleton survives better and proves to be a very good source for DNA sampling. There have been a lot of techniques pioneered by experienced scientists in the field of DNA sampling, such as mitochondrial DNA sampling which helped determine the genetic inheritance of a man who had lived some 700 years ago.
The mitochondrial DNA does not contain the full spectrum of genetic information; only partial, but somehow it’s enough to identify the corpse and it is present in greater abundance than the “normal” type of DNA, which is nuclear DNA.
Still, the question lingers on: How long does DNA last? As you have probably concluded yourself after reading the above, there is no clear and simple answer. The survival of DNA depends on a lot of factors, from weather to the burial place of the body and how well it was preserved. This incredible molecular legacy we all leave behind is quite surprising and if nature takes care of it, it can survive for a thousand years to let our descendants know more about us and thus pass on the knowledge from one generation to another. Isn’t this exciting? We think it is very exciting and a piece of information worth knowing.