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Old 07-11-2017, 01:25 AM   #4
danthescienceman
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Location: Cambs UK

Join Date: Jul 2017
Posts: 3
Default thanks, plus follow up question

great advice, it fits with what i was thinking

Quote:
Originally Posted by Carcharodon View Post
There's a lot to unpack here, but I can give some advice!

It's the timing here that is the critical factor. For example, I've sampled shark tissues on 2x consecutive dives where samples collected earlier in the dive stayed with me for ~60 min underwater. It was CA, so the water was chilly, but not that cold. But I tended to notice that samples collected on earlier dives - or even earlier in the dive - tended to give more degraded DNA than the ones that were more immediately preserved/frozen (we'd take the boat back to the lab, and freeze at -80 C). Sometimes the difference was small, even negligible. Other times it really seemed to make a big difference.

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Did you notice if the size, or rather dimensions, affected things, i'd assume a larger specimen would freeze slower but is this noticeably different or did you chop them up first?

btw a few years ago i did some (admittedly basic) experiments on the affects of freeze thaw and found no noticeable degradation (but this was only checked on a gel as there was no long-read tech back then to worry about)
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