12/21/2020: White Out isopod genetics 101

Though roaches have been my main “thing” for years, in the background I’ve always had a lot of other projects running. Among them, a constantly churning slew of isopod morphs and localities. Many household strain names (at least those whose integrity has not been compromised by careless mislabeling and reckless mixing) find their origins in the isopod sex dungeon that is the Roach Crossing bug room. While some strains have taken nearly a decade to stabilize due to their complex, multi-gene nature (maybe I’ll release Porcellio scaber “Freckles” formally this decade), others are fairly straightforward. “White Out” is one of these; a simple recessive mutation that causes the entire isopod’s body to be void of dark pigment. Yellowing occurs in age in these lines, though it’s not sure if this is pigment or perhaps fat cell related. Regardless, this phenotype is easy to determine, but things don’t stop there.

Incomplete dominance is a phenomenon where a dominant allele does not completely conceal the traits of a recessive allele. A common example in flowers is when a true-breeding white flower (genotype cc for example) and a true-breeding red flower (genotype CC) are crossed and the offspring ( Cc ), instead of being red as in the dominant genotype, are actually pink due to the partial influence of the recessive allele. Despite its subtlety in this scenario, this effect can still be observed in heterozygous ( Ww ) “White Out” Armadillium nasatum.

In the below picture (overexposed due to lack of crustacean cooperation), the three phenotypes can be seen: on the left is the heterozygous white out (Ww) with lighter body coloration and whitish spots down the back, in the middle is the typical true-breeding wild type (WW), and on the right is the “White Out” (ww). Thus, separating out the first generation of wild type to mutant crosses is simplified by selecting just the hets. A glorious example of textbook Mendelian inheritance!

Left to right: Het. “White Out”, wild type not het., and “White Out”.

In the context of some questionable labeling and culturing policies, the fruit of many isopod keeper’s years of time and hard work collecting and isolating different traits can surely be lost. Roach Crossing strives to provide true-breeding, properly-labeled and tracked isopod lines. You will never see my “Orange” and other lines produce wild types or other atypical traits and if you do… let me know. I’ll want them back for isolating!

-Kyle