I have been trying to integrate a simple unc-122p::GFP array after microinjection by using the protocol on WormBook. I have repeated this twice, each time singling around 150 fluorescent progeny of the UV-irradiated worms. Starting from a strain with around 20% transmission, I have a couple of plates with much higher transmission, say 80 or even 90%. I thought these may be heterozygous integrants, so I singled 10 fluorescent progeny from 10 of these plates. However, this never leads to a homozygous strain, so presumably the integration wasn't successful, but how is it possible that theysuddenly show such an increased transmission nonetheless? And what could I do differently to get a proper integration? Thank you for your advice!