5/25/2022: Variance in simple recessive expression between Porcellio scaber strains, ISOPOD KEEPER MUST-READ!

This is a huge confirmation of something I’ve suspected all along: simple recessive traits can express very differently in different localities of the same isopod species.

While this makes sense to some, “big isopod” has been excessively critical of my purist mentality, causing much irrevocable harm to captive stock of both wild localities and strains. I could rant all day on the destruction done to lines like my beloved “Magic Potion” ( no US or Japan label, as there is only one true “Magic Potion” strain ) There is now irrefutable proof against one of the tenants that has been shouted from the soapboxes of isopod discourse since 2018: that an orange is an orange, a white out is a white out, a dalmatian is a dalmatian, etc. This has been used to justify reckless, apathetic, and greedy mixtures of strains under the deception that simple recessives commonly revert in a pure culture (the odds of which are possible, but ridiculously unparsimonious) OR that one can just “select for” the simple recessive phenotype to completely undo the effects of strain mixing and have a line that is 100% indistinguishable on any level from the original strain it claims to be.

Months ago I noticed a solid white individual in a colony of Porcellio scaber Lava x previous failed White Tiger. Immediately my ambitions swelled at what would be a new iteration of the white out gene in a new line… until I remembered that I had used the failed White Tiger genetics, thus putting the leucistic allele into the mix. This was huge, as leucism as expressed in “Lucy”, a pure US scaber strain, is distinguished from white out by its solid black eyes… yet here was an individual with white eyes.

I pulled this individual and kept her isolated for many months to ensure she cleared out any sperm she may have had (she never produced any offspring during this time, suggesting she wasn’t mated when pulled), then added a true-breeding leucistic from “Lucy”.

Some time later, babies popped up, but were too small to confirm phenotype. I waited longer, until finally… black eyes, all around. This confirmed that the same simple recessive leucistic allele was responsible, as the separate white out allele crossed to leucistic would produce an F1 of double hets. that would be lighter in color but still definitively gray as is the primary wild phenotype.

So what does this mean? It means that underlying traits in “Lava” (most likely the multi-gene/modifier influenced orange/orange calico traits) are affecting the phenotype of the simple recessive leucistic. This makes sense, because in a more demonstrable manner double homozygous recessive lines like “Spottergeist” alter the mutant phenotype noticeably. However, this is the first definitive instance of unselected or passive latent characters of a strain having a dramatic effect on the cross-strain phenotype. A very… black and white effect, if you would humor me.

The damage from imprudent strain mixing has already been done, and surely some nifty true-breeding strains will emerge from the rubble (that’s a joke, as they haven’t). But for those clinging to pure cultures or who have managed to source pure stock of old and new favorites, let this discovery galvanize your resolve to value and preach its importance.

-Kyle