Meet the Man Who Invented Sexless Oysters
Photos by the author.

Meet the Man Who Invented Sexless Oysters

Because oysters take on a very particular flavor during spawning season, geneticist Standish Allen created a sexless, freak oyster that could be consumed year-round.
February 4, 2016, 5:00pm

Oysters are the most sexual creatures in the animal kingdom: their flesh literally morphs into a reproductive organ during the spawning season, which in Australia, runs from around December to February.

During these summer months, oysters are intensely creamy, milky, and full-bodied. Some people enjoy the experience. Traditionalists, however, limit oyster eating to non-spawning months—according to French lore, those that have the letter "r" in them.

But back in 1979, in a lab deep in Maine, the geneticist Standish Allen was meddling with chromosomes to create a sexless, freak oyster, which could be consumed year-round. His theory? Create a tri-chromosome creature that, because it was infertile, would not spawn and could feed the masses' insatiable appetite—rain, hail, or shine. It worked.


Standish Allen.

While most creatures (including human beings) are diploid (we have two chromosomes), Allen's invention has three. Because the triploid doesn't waste its energy breeding, it grows faster, larger, and is less susceptible to disease. While the idea failed to take off at first, 14 years later, Allen created yet another creature, the tetraploid (four chromosomes) which, when mated with the diploid, produced the magic, tasty triploid. That's when production became viable.

We gave Allen a call to chat about about mollusk sex, oyster sentience, and humanity's arrival at the necessary evil of modifying foods.

MUNCHIES: Hi, Standish. Do you remember the first oyster you ate? Standish Allen: It wasn't one of those epiphanal moments like, 'Ah! I gotta look at that for the rest of my life!'

And now? I like them, a lot. Actually, I prefer the triploid at the right time of year. When diploid oysters are fully ripe, you can by far taste the difference: It's the difference between a sort of sweetish, full mouthfeel on the triploid versus a sort of mushier and more fatty-like mouthfeel to the ripe oyster.

So the triploid serves the function of being edible all year-round, when the regular oysters aren't so palatable. Can you describe the taste of a spawning oyster? Oysters in Australia are very commonly eaten in the holiday season, which, on the wrong side of the world, is actually summer. So it's very common for people in Australia to eat spawny oysters and not think anything of it.

sexlessoysters_dip trip 2

I've had the experience of eating one. I found it rather … unpleasant. The first time you eat it, you wanna gag. But the be-all and end-all of having a triploid is not simply for better market quality. It was definitely one of the very first arguments and it still pertains if you have an aversion to eating spawny oysters.

But there's a second aspect: Once an oyster develops a whole bunch of gonads after that period, when the oyster has expelled all that, then it becomes a thin, watery, barely marketable product.

And how long does that flaccid period last? Oh, probably a couple of months, until the oyster builds itself back up again. Oysters are crazy sexual creatures; they literally devote the most energy in the animal kingdom to reproduction. That's their evolutionary motive: to create lots and lots of kids, because their lives are so tenuous.

What an oyster does when it gets reproductive is it actually transforms [its] body tissue into gonads. So if you want to put it in laymen's terms, think about the flesh on your bones changing into eggs and sperm that when you have sex, there gonna, like, eject completely! So what does that leave you with? Hell! Now you're emaciated.

Kinda like love, huh? Hah! Yeah, you're going to have to rebuild!

So these creatures have these pathetic, tenuous lives, which revolve entirely around sex—isn't it kind of mean to deprive the triploid of that? Isn't it kinda mean that I eat them alive? If I ever thought oysters had feelings, I'd probably have second thoughts about it.


So on the spectrum of sentience in the animal kingdom, where do you place them? They're pretty far down on the scale. They don't have brains. They have a couple of nerve points called ganglia, which we have all over our bodies, and that certainly reacts to stimuli. But I'm not going to attribute feelings to them.

You actually invented triploids twice: first in the 70s and again in the 90s. Why didn't it take off the first time? We had this hypothesis that if you made a normally diploid animal into a triploid, it would have reproductive issues. So the first step was to change the triploid into a diploid. That's done by manipulating events immediately after fertilisation. Our experiments and work thereafter with commercial companies showed you could do this at a fairly large scale; you could take half a billion eggs and crank out quantities of triploids that are made artificially. We call those "chemical triploids" or "induced triploids" (it's a little bit more benign).

As it became clear that the triploids were useful and more and more companies wanted to commercialise it, the only way they could do it was to do it with this induction method, which is fairly inefficient.

Later, we came up with the next step, which is tetraploids—an additional set of chromosomes over and above the triploid set. That was in about [1993].

The diploid can reproduce because it can divide its genetic chromosome in half. A triploid is reproductively constipated because it can't divide three into two very well, but then when you get up to tetraploid again, the biology recovers. So, if you take a tetraploid and you cross it with a diploid (both of which can reproduce), all their progeny are triploid. That allowed the production of triploids to just explode.

It took a little while for the technology to make its way into commercial hatcheries, but by the late 90s and early 2000s, hatcheries were picking up this technology as early as they could adopt it.

But the process isn't GM, right? So how would you describe it? What's happening to the oysters here? Well, it's along the lines of what agriculture has been doing for thousands of years—a form of selective breeding, which alters the nature of the inherent genome but doesn't add additional material to it.

In agriculture, there are numerous examples of polypoid species that we eat without even thinking about it, like bananas, seedless watermelons, blueberries, strawberries, and all kinds of flowers. There are some naturally occurring polyploids but the agricultural species have been manipulated for production.

What are your thoughts on GM foods? I often hear people use the word "scary" when they refer to GM. I think many of us don't really get what's changed about the food that we're eating.

Well, this is where it gets philosophical. It's about humanity—the throngs and the need for feeding them … How are you going to overcome some of the agricultural challenges in arid environments or nutritionally deficient species if you can't manipulate them to feed the throngs of humanity?

I don't think it's great that we're in that situation, but we are. Largely, the whole GMO thing is done in response to that unsatisfied demand and unfortunately, it's been done at a commercial level where there's also an element of greed involved. Why should anybody have intellectual property [rights] on a creature that you're going to use for sustenance? I think GMOs are a response to the needs of our unsustainable population.

At the moment, it's not an obligation to tell the buyer if they're getting a triploid or a diploid. But if it were, "triploid" is a kind of scary name. So, what would you call them to make them sound cute and delicious? The Aussies have it all over us when it comes to euphemisms! They don't use the world triploid, because all that does is invoke a whole lot of other questions: What's a triploid? How's it made? Is it a GMO? So they use the term "spawnless oyster." A lot of people have used the term "four-season oyster," which kinda gives it a little cachet—maybe sounds like it came from a hotel. But you could call it "the chromosome sweet." (You probably don't wanna use the word "chromosome"!) Something that implies you've got an improved mouthfeel.

Thanks for speaking with me.