| Methods, Phase (2) |
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A two-minute refresher on genetics. Methods, Phase (2) How I'd do it, but my wife won't let me. An open letter to the breeders and distributors. Download this entire website as a [PDF] document. |
If you have found your way to this page, you have a sibship of juvenile mystery snails from an ivory mother, probably from an egg mass that you hatched yourself. If you have just completed Phase (1), you have already sent me a photo (or photos) documenting what this sibship looks like. If you skipped directly here without passing through Phase (1), you’ll need to send me a photo or photos of whatever babies you’ve got first. In either case, the overall research concept in Phase (2) is just as simple as Phase (1), but the logistics are more difficult. We will mate our F1 mystery snails in controlled fashion, ideally by testcross. So if, for example, your F1 sibship of mystery snails contained just ivory and gold, I’d ask you to simply set up a bunch of ivory x gold pairings, with as many pairs of juveniles as you’ve got. Our hypothesis will be that your golds are aaYyss, and ivories are aayyss, and we will expect a 1:1 result in their F2. The situation might be more complicated than that. If (as another example) your F1 sibship contained jade, gold, blue, and ivory, I’d (probably) ask you to pair all your ivories with jades and set aside your golds and blues for now. Our hypothesis here is that your jades are AaYyss, and (of course) your ivories are aayyss, and we are now expecting 1:1:1:1 in their F2. And we have a test for linkage. More about linkage later, as the MSCG Project unfolds. The special case would be if your ivory mother yields all-ivory F1 offspring. In that case, we will need to send you some babies of some other color form. Stand by. The bottom lines are that before moving forward in Phase (2), you need to contact me for specific instructions. I will be back in touch with you to suggest the preferred F2 crosses…. … and that your crosses must be done pairwise – just one pair of snails per container, nothing else. I am leaving the Phase (2) culture details to you, just as I did in Phase (1). I feel pretty sure that you’ll want to start with some sort of vessels smaller than a typical home aquarium. If you’re interested in my recommendations, click on the link above entitled, “How I’d do it but my wife won’t let me.” But these are your snails and your space and your time and your money, and you’re the boss. Select your own culture vessels, use the diet you think is best, change water according to your own schedule. Some mortality is inevitable, and some juveniles will probably fail to thrive and grow. So if you begin, for example, with ten gold x ivory F1 pairs, some juvenile golds will die, and some juvenile ivories will die, and you will need to combine their widows. That’s one of the main reasons I would not begin my Phase (2) crosses in large aquaria, if my wife would let me. I’d want to save space and money. There’s no point in purchasing and mounting ten big aquaria if you ultimately only need four. After some months in culture, we will expect our F1 x F1 pairs to yield F2 offspring. Or perhaps not. If the sex ratio is 50:50 (which seems optimistic) at most half of your F1 pairs will yield offspring, and the other half will be matched-sex. Probably less than half will yield offspring. Maybe a lot less. So at some point, as your snails reach maturity, it will probably be helpful to rotate partners around. In other words, leave all the snails of one phenotype in their aquaria, and move all the snails of the opposite phenotype one aquarium to the right. But on the plus side, it will not be necessary for all your F1 paired snails to yield F2 offspring. If you started with ten gold x ivory pairs, and six died, and half of the four surviving pairs were matched-sex, the two pairs that ultimately proved viable and fertile will almost certainly yield enough F2 offspring to qualify as a success. Treat the F2 offspring exactly as you treated the F1. Count them immediately and separate them by any color phenotypes you are able to distinguish. Rear the F1 to at least pea size, count again and verify phenotype. Report your results to me by email, with attached photograph or photographs to document your results. |
Last updated 7 Nov 2018