Jillfishie
Your color sorting practices holds no merit distinguishing BGJD from NON BGJD, it's a recessive genetic trait that isn't visible to the naked eye. You may be picking JD for a certain color hue and that's about it. Do you think you and your teacher are the only wise people who've worked with these fish to date? Don't you think the person who discovered the trait in his stock worked all the possible genetic/phenotype angles before the fish were released. I've seen/read these color sorting claims from seller(s) on AquaBid, it's just a way to sell JD that may or may not have the blue gene at a higher price.
I'm only rebuffing your post as they shouldn't be perpetuated any further. If anyone wants to dig deeper visit these 2 sites and start posting your ideas there and see what unfolds, both are JD specialty sites that have some of the most/best/experts on breeding EBJD and JD in general. I've learned a lot there.
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no advertizing of other websites or forums here @ MFK
-Website Removed-
no advertizing of other websites or forums here @ MFK
Let it be said I'm not trying to get you to stop your practices on color sorting your stock, continue on you'll probably have some the best color/line breed JD out there blue gene or not.

On the other hand I also hope you poke around on the sites provided if you have the time and do some posting there too.