I have just ordered a few dumpy strains from CGC and am planning to make my own frozen stock.
WormBook says some mutant strains, especially some dumpy strains, don’t survive as well as wild-type worms,
so I was wondering if there’s anything I can do to make freezing work better?
I guess the words to hold in your mind are ‘not as well’, so you are likely to get fewer live ones per plate when you thaw a vial out. It’s not that all Dpy strains are the same and it’s not they all die.
Suggestions: stick to the established protocols (Wormbook), freeze regularly (and check the batch with a thaw out of one of the frozen vials a short time later), don’t freeze a mishmash of worm Ages, get’em young.
The most notoriously difficult-to-freeze strain I’ve personally frozen is dpy-10(e128), and I had no trouble with it. I can only recommend that you follow normal best practice: use clean plates (no bacteria other than your normal food source, no mold or yeast), with a high titer of freshly starved arrested L1 worms (wait until all the eggs are hatched, but not much longer). Freeze with normal methods, in liquid in a styrofoam box for slower cooling (not that I know the styrofoam helps - it’s just part of the normal protocol). The soft agar method saves on freezer space and possibly on time because you refreeze the worms less often (though I’m not convinced of the latter - you may be able to thaw from one tube multiple times, but each thaw is a bit more work and less likely to succeed), but from what I’ve heard and seen the when compared to freezing without agar the soft-agar method is likely to give an enormously lower concentration of viable worms, in much worse condition.