Hi Drosophila workers! I have a question concerning embryo viability
that I hope one or more of you will know the answer to. After I have
collected embryos on an egg-laying plate, and allowed them time to
hatch, I count egg cases and unhatched eggs to determine viability. The
majority of unhatched eggs are white; a small minority are brown. I was
told by a resource here to consider all the white ones as unfertilized
and the brown ones as fertilized (and obviously dead). I'm not
convinced that all the white unhatched eggs are unfertilized - some are
homogenously translucent, some are clear at the poles with a clump of
white in the middle, etc. Most are covered by the chorion so one cannot
see into the egg. Does anyone know how to tell, using a dissecting
scope, whether an unhatched 36-60 hour old embryo is fertilized or not?
Are there some visible changes inside the embryo that would be clues to
whether it is fertilized or not (again, at the dissecting scope level)?
THANK YOU! my e-mail is wheelock at hawaii.edu. Anne Wheelock