I Dream of Purple Mushrooms

Andrew has been running an extensive oyster mushroom breeding program for a couple of years now, and if you’re reading this you are probably familiar with some of the fruits of that labor. The King Blue, Mother of Pearl, Super Scallop, and Watercolor Oysters all came out of his lab and were tested in our grow rooms. What you may not know is the true scale of that program. For a single pair that were crossed, we have 136 strains that have been kept and cataloged for further testing because of some early detection of a desirable trait. That’s probably about a tenth of the number of strains that we actually grew trials of, most of which are either undesirable or not a noticeable improvement over the parent strains. That’s just one cross, and Andrew has run dozens of crosses and isolates by now, so we’ve seen a lot of experimental mushrooms run through our grow room. Out of all of these, there’s one mushroom that haunts my dreams: the purple oyster.

It must have been beginner’s luck, because it was one of the early crosses we ran. Andrew still hadn’t gotten the process systematized, and so when harvest time came the purple mushroom was picked and sold to a restaurant. Because it was one of the first sets of trials, Andrew figured that it wasn’t a big deal, we’d see it again. He kept breeding that same cross over and over again. No luck, that little genetic anomaly is apparently far more rare than we could have guessed. We’ve still gotten some good results, but that purple has been more elusive than a polite political discussion.

I was informed, however, that we may have had a breakthrough. Andrew has finally seen a mild lilac color on a test oyster! It’s not very robust, not the stalwart lavender of our fallen comrade, but it’s a start. We will certainly be breeding back on that little bastard to try to further develop the color.

Genetics is a fascinating subject. Quick primer: generally speaking, genes are either dominant or recessive. We get one set of genes from each of our parents, and our physical traits develop as a result of how they match up. AA, Aa, aa, this is one way these gene pairings can be notated. If a trait is dominant, then AA or Aa will express the gene, considering that the lowercase letter is the absence of that gene. If the gene is recessive, then only if both parents provide a copy of the gene, (AA) would the gene be expressed. Some genes provide a direct effect on a physical structure, while other genes are modifiers that change the way another structure is expressed. This is a vast oversimplification, and it’s been years since I’ve studied any of it, so we’ll just assume that I’m probably wrong about half of what I’m saying anyway.

That said, I used to be married to a dog breeder who loved color genetics. In Chihuahuas, there’s a gene for black fur that affects the whole body. It is dominant, so if either parent provides that gene, the child will be a black base. If not, then it will have a red base coat. Beyond that, there’s a dilute gene that turns a black base to blue and a red base to cream. Then there’s a chocolate gene that turns the black base to brown and I can’t recall if it had any effect on a red base. Both of those modifiers are recessive, so they had to come from both parents for there to be any effect on the puppy. A dog who has a black base with both dilute and chocolate from both parents will be a lilac. These are quite rare, and because it takes extensive breeding to express a lilac coat, there are often other underlying issues with the dogs, so many breeders aren’t very stoked on other breeders who focus on color. In order to develop recessive traits, often line breeding is performed, where a dog is bred back to one of its parents to increase the likelihood that the offspring will get two copies of the desired trait. Family vines are an interesting phenomenon in the world of exotic dogs.

Mushrooms are even weirder, though. There are a number of factors that go into whether two oyster mushroom spores are compatible, but there’s really no mommy or daddy oyster, so a mushroom can easily breed with itself. Even vines have some branches, we’re talking about family ropes on this pedigree! That said, spores are produced literally in the billions per cluster of oyster mushrooms, so when breeding a cross, unless intense care is put in to isolate a single spore from each parental candidate, there’s a very real possibility that any offspring from the cross could actually be an isolate, or a child of two spores from the same parent.

You see the dilemma: I’ve had a pregnant bitch that we didn’t know who the daddy was, but this is bizarre – we actually have 3 potential parentages from an attempt at a cross.

1 – Mom x Mom

2 – Mom x Dad

3 – Dad x Dad

So any time we see a particular trait expressed, we don’t know where the gene came from. Mushroom pedigrees have a lot of question marks on them unless you just take spores from a single parent, but that’s not as fun. Furthermore, tracking whether a gene is dominant or recessive is difficult, because if a baby mushroom has the trait, it very well could have been a recessive trait in a single parent that actually ended up breeding with itself! This is why Gregor Mendel used peas in his early study of genetics. If he started with oyster mushrooms, we’d still be scratching our heads over his notes…

All this said, I want a purple mushroom. It haunts my dreams not because it is a vision of what could be, but because it is a memory of the most terrible sales tragedy I have ever seen. A vision of what was, and was lost.

That little lilac oyster is gonna have a lot of babies!