In previous articles, we have described the entire path of the sample from sampling to results and their interpretation. If biological sample (swab, blood) was of high quality a lot of isolated DNA remains after the analysis, and it can be stored for reuse.
The DNA molecule is stable for a very long time under favourable conditions. Rapid advances in DNA technologies make it possible to obtain information from archaeological and paleontological remains. Thus, we can study the genetic links between extinct organisms and their modern relatives. Scientists can use the DNA molecule of organisms that lived before the advent of the Neanderthal. There are also studies on dog samples from more than 10,000 years ago.
The stability of DNA isolated in the laboratory is influenced by various factors from storage temperature, purity/the quality of the sample from which the DNA was isolated, the protocol used for isolation, the DNA sequence, and the exposure to light or UV radiation.
DNA is stored in a refrigerator at +4 °C for a short period of time, but in the case of good quality it is stable for several years in such conditions. Despite the good stability of DNA at +4 °C, it is better to store it at −20 °C or −80 °C for long-term storage. Sensitive DNA samples can be stored in liquid nitrogen at −196 °C. Such storage is used only for extremely sensitive samples (e.g. archaeological samples).
In our laboratory, DNA samples are stored at −20 °C for several years. And why do we keep DNA samples at all? DNA samples are stored so that they can be reused at the customer's request in the event of new discoveries and new genetic tests.
New technologies in the field of DNA enable very rapid detection of new mutations associated with various genetic diseases and physical traits (hair colour, tail length, etc.). At the time of writing, about 300 mutations are already known in dogs, but the number of these is rapidly increasing. Newly discovered mutation is followed by the development of a genetic test and the offering of this test on the market.
If you have sent a sample to our laboratory in the past, it is stored in most cases. In case you want to order an additional genetic test for the same animal, it is not necessary to send a new sample, as many different genetic tests can be performed from the existing sample. This will avoid the stress of taking the sample again, sending it, and doubting whether you took the sample correctly.