There are some species that have hundreds and even thousands of sexes and mating types.

Let’s talk about sex. It’s defined as either of the two main categories — male and/or female — into which humans and most living organisms are distinct on the basis of their reproductive functions. That’s basically the definition of sex, but as usual, that’s not what nature has in stock. In certain organisms, it is possible to be both sexes at once as a result of genetic mutation — that’s termed as hermaphroditism. It stunned evolutionary biologists that some species have not just two, but multi varieties of sex. That’s way too sexy.

Related media: How Sex Genes Are More Complicated Than You Thought

Let’s Get Really Sexy

In humans, our sex is determined by genetic chromosomes — X and Y — with females having two X chromosomes, and males having one X and one Y chromosome. But that’s not always the case, there are a few people whose biological sex is not the same as their sex chromosomes — such as XX males and XY females, and even extreme but rare cases of people whose sex chromosomes might be XXX females and XYY males. The contrast between the sex chromosomes you inherited biologically from your parents, and as a result of how people identify you, is quite a different story in our culture today.

Sexes are solely determined by genetics, and that’s up to nature to decide, yet oftentimes, organisms have some peculiar traits that are really a mystery. For instance, sea horses have both male and female sexes as most organisms, but in their case, the female lays the eggs and transfers them into the male to have their offsprings delivered — like we said, weird. Can we still call that “insemination?”

“I often like to view such complex issues through the lens of life’s diversity.” Antonis Rokas, an evolutionary biologist at the University of Vanderbilt, writes in an article to The Conversation. “I believe that studying the reproductive strategies of fungi, and how the sex of these organisms is determined, offers a bewildering, but also fresh and surprising perspective of the sheer diversity with which, well, these organisms do it.”

The Masters Of Sex

The fungus is a really weird heterogeneous organisms. They are mostly embedded in their own food and have the ability to digest their food externally. Baking yeast, molds in cheese, and mushrooms are a few examples of fungal organisms.

In humans, there are two basic sexes, but sex in fungi is weird; as Rokas explains, is controlled by a specific and relatively small region of DNA on a chromosome — technically called locus. The sex locus of the baking yeast, for instance, contains two different gene variants, which is quite similar to that of humans — it means the organism has two sexes or mating types, and individuals can mate with opposite sexes.

On the other organism, certain forms of mushrooms have similar two genetic areas that determine their sex. Rokas also explained this as: The two sexes being A and B; but instead of the two variants, the A and B areas each could also contain multiple variants. Say A1, A2, A3, and on, and B1, B2, B3, and on. Each individual’s sex is determined by specific combination of genetic variants in both areas, and the number of possible sexes multiply within these organisms: A1B1, A1B2, A2B1, A2B2 and on.

“Given that some species of mushroom-forming fungi harbor dozens to hundreds of A and B region variants, it is estimated that these organisms contain thousands of sexes.” Rokas writes.

It was no surprise that a professor at the University of Kentucky, Lisa Vaillancourt, got inspired that she created a “fungal mating games” for her students. Like seriously, we’d really like to play this game of sexes. We hope its as sexy as the name suggests.

Multisexuality: That’s A Thing

Surprisingly, fungal sex doesn’t end right here. Rokas continues: a key aspect of the sex life of the baking yeast is worth mentioning, they are capable of switching their sexes — a strategy evolving from their ability of mating with siblings of opposite sexes. Other fungi, like the mold Aspergillus fumigatus, happens to be a major fungal pathogens that affects humans, has the same bi-sex feature as the baking yeast, but lacks the ability of switching sex.

However, another penicillin-producing mold, Aspergillus nidulans, a close relative of A. fumigatus, has both variant sex locus in their genome. This give them the ability, and choice, to either self-reproduce, or to mate with another, as Rokas concludes.

Here’s a list of organisms that are known to be multi-sexual:

Saccharomyces cerevisiae

Saccharomyces cerevisiae, whose individuals have the ability to switch between two sexes.

Aspergillus nidulans

The penicillin-producing Aspergillus nidulans, whose individuals contain both mating types.

Candida albicans

Candida albicans can undergo parasexuality, a process that confers the same genetic benefits as sex but that doesn’t involve the same mechanisms.

Schizophyllum commune

The split gill mushroom, Schizophyllum commune, is a species estimated to have 20,000 or more distinct sexes.

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Written by: Nana Kwadwo, Wed, Jan 23, 2019.


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