Herbarium specimen can be used for Molecular studies??? : 3 posts by 2 authors. Attachments (2)
In a previous thread it was discussed that molecular techniques may not be applicable to herbarium specimen.
I was under impression that it can be, some vague memory of something i had read outside of medical literature.
i feel herbarium collections esp those that are well cared for and also seed banks are a great resource for many centuries to come…. hope for my next incarnations….
any way recently going thru some old emails I had not opened ran into one by Arun Pandey forwarded by Garg ji in november 2015 had a pdf about herbaria in a BSI magazine I surmise… there is no citation given as to the magazine … but may be its Down to earth … the pdf is to be found in our group site at this link.
on its page 5 of 12 pages is a text box that reads Correct the errors….
seems to give hope to my notion for future…use of herbarium collections for genetic analysis of sorts
I am enclosing a picture of that textbox and a copy of that pdf in case the original link does not let you download the file..
this is not to correct anybody or play any ego game on my part but i need your inputs scientifically…
i would like your opinion about this paper ‘s assertion…
Your basic question is, can herbarium specimens be used for genetic studies?
Basic answer is ….IT DEPENDS!!!
To understand this we need to understand that DNA is very sensitive to water and it can degenerate not just with water but also by chemicals which are used in curating the herbarium specimens. Some herbaria like ours in Hong Kong do not use any inorganic chemicals as we claim to be totaly organic. To kill pests, we use sub-zero temperature instead of chemicals.
A herbarium specimen once collected, needs to be dried. Usually drying is a slow process which degerates the DNA. Some peopl use hot dryer to dry the specimens and hence DNA degerates also due to heat. BUT NOT ALWAYS. If you use some fast drying methods like cold drying then you may get the DNA extrracted out of it.
On the other hand, a DNA/genetic study is not considered complete unless you have a specimen collected with it and deposited at a registered herbaria. So researchers collect sample of the plant for herbarium specimen and a small piece of leaf is cut and put in silica gel FOR FAST DRYING. This helps in proper extraction of DNA. Or some researchers use fresh leaves for extracting DNA.
Some specimens could be 100 years old or more, it is almost impossible to extract DNA from them as far as I know but obviously it is not impossible as I said, it depends how they dried it. For example in the case of water melon example.
The article is here but in the article they didnt write how they got DNA out of the herbarium specimens. But this may be the only successful case so far.
that explains the failure some report in using herbarium specimen.
What is cold drying? How is that accomplished?
In case oif this watermelon story, they seem to have used at least one set of herbarium specimen from 1700s
in those days did they have silica drying or cold drying, and i know they did not have the extra collection and storage for DNA analysis etc .
Silica drying seems to be the most efficient way so far… in hot and moist areas like our state of WB