I guess it's the downside of screening. I'm essentially going in the morning and collecting virgin* flies from 350 crosses, crossing these flies to other stocks, having lunch and then repeating the process in the afternoon. Over and Over again.
I guess it serves me right for picking a gene on the X chromosome. This means I have to go for the "maiden" female flies as there's the possibility the mutation may be lethal which isn't so great if you're a male and only have the one X chromosome to play with . It also means that all the males from the crosses are potentially ones where the deletion hasn't occurred so there's no point in using them at all. I was planning on doing some courtesy PCR on the males in the sense that if there is a deletion I'd know it isn't lethal. I haven't really had the time though. I'll probably wish I made the time if it turns out it is a viable mutation and I could have just picked a bunch of males from each line ONCE rather than twice a day for a week. Let's not think of that though.
Next week, I can at least change the repetition of virgin collecting (not as fun and/or sinister as it sounds) with serial fly squashing (essentially as sinister as it sounds) and PCRs.
I have another mutagenesis screen on the go too but fortunately that one isn't on the X chromosome so it will be an absolute breeze by comparison. Unless it's not.
*Just in case you think I'm some kind of kinky drosophilist I should point out that flies use internal fertilisation to reproduce (like most people do) and not externally by the female dumping a load of eggs and then the male does his manly duties over said laid eggs. For this reason, when doing crosses you need females that haven't mated with their brothers (flies are cool with Game of Thrones plotlines) or you will wind up with progeny you don't really want.
They do it doggy style in answer to your inevitable follow-up question. In terms of "how do you know they are virgins" - you can do it based on time or you can check if they have a black spot on their belly. If they have a spot they are still virgin. It's definitely a talking point at interviews if you put that one on your CV.