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>The samples were then cryogenically stored at -112 degrees Fahrenheit for around two decades. So "scientists" stored DNA for 20 years and then decided to take

by 1970-01-01 4y ago

>The samples were then cryogenically stored at -112 degrees Fahrenheit for around two decades. So "scientists" stored DNA for 20 years and then decided to take a closer look? Better than nothing, but not by much.

jostmey 4y ago
DNA sequencing wasn’t an economically feasible option 20 years ago
- 1970-01-01 4y ago
  OK 20 years maybe it wasn't worth the cost, but by 2011 it was only thousands of dollars. https://www.genome.gov/about-genomics/fact-sheets/DNA-Sequencing-Costs-Data https://www.genome.gov/about-genomics/fact-sheets/DNA-Sequen... https://en.wikipedia.org/wiki/DNA_sequencer#Comparison https://en.wikipedia.org/wiki/DNA_sequencer#Comparison
- bergenty 4y ago
  Well you’re not addressing the GPs concerns. The DNA could be severely damaged.
klyrs 4y ago
If they did analysis using tools and methods that weren't available / affordable 20 years ago, then preserving the samples for that long might have been wise.
anarticle 4y ago
Ouch, it is not uncommon to freeze samples for a long time, especially rare ones like this. You're free to peruse the literature on how this is an accepted practice.
- 1970-01-01 4y ago
  So I did. Searched and read about it, found out the viability and recovery of cryopreserved PBMC has a clear downward slope. Samples are good for years, not decades.
  - anarticle 4y ago
    This depends on what you want to do. The DNA can certainly be sequenced. They might even be viable if you’re nice to them. What I mean to say is this is an accepted practice in many labs, including ones I have worked in. In my experience, these were old tumor cells stored in LN2. Sources include: https://link.springer.com/article/10.1007/BF01131376 https://link.springer.com/article/10.1007/BF01131376 https://pubmed.ncbi.nlm.nih.gov/9336042/ https://pubmed.ncbi.nlm.nih.gov/9336042/ https://pubmed.ncbi.nlm.nih.gov/27792414/ https://pubmed.ncbi.nlm.nih.gov/27792414/

jostmey 4y ago

DNA sequencing wasn’t an economically feasible option 20 years ago

1970-01-01 4y ago
OK 20 years maybe it wasn't worth the cost, but by 2011 it was only thousands of dollars. https://www.genome.gov/about-genomics/fact-sheets/DNA-Sequencing-Costs-Data https://www.genome.gov/about-genomics/fact-sheets/DNA-Sequen... https://en.wikipedia.org/wiki/DNA_sequencer#Comparison https://en.wikipedia.org/wiki/DNA_sequencer#Comparison
bergenty 4y ago
Well you’re not addressing the GPs concerns. The DNA could be severely damaged.

klyrs 4y ago

If they did analysis using tools and methods that weren't available / affordable 20 years ago, then preserving the samples for that long might have been wise.

anarticle 4y ago

Ouch, it is not uncommon to freeze samples for a long time, especially rare ones like this. You're free to peruse the literature on how this is an accepted practice.

1970-01-01 4y ago
So I did. Searched and read about it, found out the viability and recovery of cryopreserved PBMC has a clear downward slope. Samples are good for years, not decades.
- anarticle 4y ago
  This depends on what you want to do. The DNA can certainly be sequenced. They might even be viable if you’re nice to them. What I mean to say is this is an accepted practice in many labs, including ones I have worked in. In my experience, these were old tumor cells stored in LN2. Sources include: https://link.springer.com/article/10.1007/BF01131376 https://link.springer.com/article/10.1007/BF01131376 https://pubmed.ncbi.nlm.nih.gov/9336042/ https://pubmed.ncbi.nlm.nih.gov/9336042/ https://pubmed.ncbi.nlm.nih.gov/27792414/ https://pubmed.ncbi.nlm.nih.gov/27792414/