A two-minute refresher on genetics.
Hypothesis
Methods, Phase (1)
Methods, Phase (2)
How I'd do it, but my wife won't let me.
An open letter to the breeders and distributors.
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At the risk of sounding even more like your high school biology teacher than I already do, science is the construction of testable hypotheses about the natural world. We can’t just cluelessly cross every mystery snail with every other mystery snail and hope to figure out the inheritance of shell and body pigmentation from the results. We must start with an hypothesis.
For quite a few years, hobbyists have informally suggested that color polymorphisms in mystery snails are controlled by three genetic loci, each with two alleles. I don’t know who first offered this hypothesis, but it has been featured on Stijn Ghesquiere’s applesnail.net for a long time. This hypothesis would lead to eight discrete color phenotypes, which jives with general (although not universal) experience.
Let us call locus A body color. And let us hypothesize two alleles, the dominant A, which encodes dark pigment, and the recessive a, which does not. Homozygous recessive aa snails have unpigmented bodies.
Locus Y controls shell background color. Again we hypothesize two alleles, the dominant Y encoding the deposition of a yellow background pigment on the shell, and the recessive y not. And again, homozygous recessive yy snails have no background shell color.
Locus S controls shell striping. The dominant allele S encodes dark, purplish stripes on the surface of the shell, and the recessive s does not. Again, homozygous recessive ss snails have no striping.
Then using a blank underline to designate any second allele, the eight phenotypic classes will be:
Brown A_Y_S_
Jade A_Y_ss
Purple A_yyS_
Blue A_yyss
Chestnut aaY_S_
Gold aaY_ss
Magenta aayyS_
Ivory aayyss
OK, that’s science. We have constructed a testable hypothesis about the natural world. Now let’s test it.
Up next... Methods, Phase (1).