- #1
Jarfi
- 384
- 12
How would I store human DNA for decades, at room temperature, blood samples and not too invasive methods available. It needs to be 100% undamaged and usable for genome mapping.
Borek said:I believe for military purposes (identification of bodies) they store blood poured on some kind of (blotting) paper and dried out. There is a printed sheet with form to fill and two empty circles where the blood is poured on to dry. No idea if it is kept at room temperature nor what kind of paper they use, but there is no doubt they have the technology and it is rather simple.
Borek said:What is not DIY about putting a drop of blood on the paper?
The reason for stability of DNA, RNA or protein could be attributed to the fact that the biological material binds to the matrix of the filter paper and the process of drying excludes water which is an important factor necessary for protease or nuclease to act. Binding of the biological material also binds several inhibitors which may interfere with various nucleic acid amplification methods.
Dried blood spots (DBS) on filter paper facilitate the collection, transport, and storage of blood samples for laboratory use. A rapid and simple DNA extraction procedure from DBS was developed and evaluated for the diagnosis of human immunodeficiency virus type 1 (HIV-1) infection in children by an in-house nested-PCR assay on three genome regions and by the Amplicor HIV-1 DNA prototype assay version 1.5 (Roche Molecular Systems).
For these reasons, amplification of the integrated viral genome by PCR has been the preferred method for the diagnosis of HIV infection in children for many years (11). However, this method requires venipuncture in newborns for blood sampling and preparation of lymphocyte pellets, both of which are difficult to perform, particularly in developing country settings.
Dried blood spot (DBS) samples are an interesting alternative for lymphocyte pellets since only a few droplets of blood are required and can be directly collected on a filter paper. Storage and shipment of filter papers is easy since they can be kept at room temperature and DNA has a good stability in dried samples. Finally, DBS have been used for the detection of HIV-1 genome by PCR since 1991 (3-5) with good sensitivity and specificity.
Jarfi said:It is suppost to last for decades, not years. I can do a DIY paper but I'm not sure if the blood in the paper will decompose into bacteria waste after decades.
By comparing the specimens' ages and degrees of DNA degradation, the researchers calculated that DNA has a half-life of 521 years. That means that after 521 years, half of the bonds between nucleotides in the backbone of a sample would have broken; after another 521 years half of the remaining bonds would have gone; and so on.
The team predicts that even in a bone at an ideal preservation temperature of −5 ºC, effectively every bond would be destroyed after a maximum of 6.8 million years. The DNA would cease to be readable much earlier — perhaps after roughly 1.5 million years, when the remaining strands would be too short to give meaningful information.
Storage at –20°C to –80°C may well provide adequate conditions depending on the quality and quantity of DNA desired and the time frame in which the sample will be stored. However, neither of these conditions will maintain DNA quality equivalent to maintenance at liquid nitrogen temperatures over extended time periods (e.g. decades).
In contrast to storage of DNA in solution at very low temperatures, it is also possible to store DNA dried. This can be a practical alternative for long-term storage. In addition to reducing molecular mobility, dehydration also removes water that can participate in hydrolytic reactions. There are several methods of removing water from liquid preparations; these include spray drying, spray freeze drying, air drying or lyophilisation.
To ensure high quality microarray results, we recommend the following DNA storage strategies:
- Short-term storage (weeks) at 4°C in Tris-EDTA
- Medium-term storage (months) at –80°C in Tris-EDTA
- Long-term storage (years) at as –80°C as a precipitate under ethanol
- Long-terms storage (decades) at –164°C or dried
Excellent and professional! you have my thanks.boymilk said:Here's another article of interest:
http://www.ogt.co.uk/resources/literature/403_dna_storage_and_qualitySo basically you have two options if you want to store a DNA sample for decades. You could store it in liquid nitrogen or store it dried. Both techniques will keep the DNA relatively intact for decades. If you do decide to take the dried route, you could also slow down the rate of degradation even further and therefore maximize your chances of retrieving the DNA mostly intact by keeping the sample away from heat, sunlight, humidity, oxygen, etc.
Monique said:Why would you want to do it?
Jarfi said:Legal purposes.
Jarfi said:Legal purposes.
It is possible to store human DNA at room temperature for decades by using a preservative called EDTA (ethylenediaminetetraacetic acid). This chemical prevents the breakdown of DNA by binding to metal ions that can cause degradation. Additionally, DNA can also be stored in a dry state, preventing the growth of bacteria and fungi that can damage the DNA.
Yes, any type of blood sample can be used for long-term DNA storage as long as the DNA is extracted and preserved properly. Whole blood, plasma, serum, and dried blood spots can all be used for DNA storage. However, it is important to note that different types of blood samples may have different storage requirements and may require different preservation methods.
Storing human DNA at room temperature has several advantages compared to freezing it. Firstly, it is more cost-effective as it eliminates the need for expensive refrigeration equipment and electricity costs. It also reduces the risk of sample degradation due to power outages or equipment failure. Additionally, room temperature storage allows for easier transport and sharing of DNA samples.
The quality of DNA can be preserved when stored at room temperature for decades by using proper preservatives and storage methods. EDTA, as mentioned earlier, is a commonly used preservative for long-term DNA storage. Sample containers should also be sterile and airtight to prevent contamination. Regularly checking and monitoring the storage conditions can also help ensure the quality of the DNA remains intact.
There are some potential risks and concerns with storing human DNA at room temperature for long periods of time. One of the main concerns is the potential for sample contamination, which can lead to inaccurate results. It is important to properly label and store samples to prevent cross-contamination. Additionally, unexpected changes in temperature and humidity levels can also affect the quality of the DNA. Regularly monitoring and maintaining stable storage conditions can help mitigate these risks.