A fungus with over 20k sexes | Hacker News Reader

A fungus with over 20k sexes

blogs.discovermagazine.com

87 pointsfanf242 comments

Serious question; I hope it makes sense: What makes these "sexes" and not just "individuals"?

To elaborate a bit: when I read the description, it sounds like a person could make the same claim about humanity: "there are billions of sexes: John, Jane, Tim, Judy, Juan, Maria, etc etc"

How is this different? Or equivalently, what makes a "sex" a "sex" if it's just variability within the sex chromosome, but every individual is able to create progeny with 25% (?) of other individuals.

To me, that sounds like 4 sexes.

There are 20k different sorts of genitals. More seriously, it would be chromosomal differences I guess.

> what makes a "sex" a "sex" if it's just variability within the sex chromosome, but every individual is able to create progeny with 25% of other individuals?

I haven't read the article yet (looks like it's been DOSed by traffic from Hacker News?), but your criterion would be met in a population of 201 entities (numbered from 0 to 200) where each entity X can procreate with entities in the range [X-25 ... x+25] (mod 201, of course). That would arguably yield 201 distinct sexes, where each individual is sexually compatible with 25% of the population.

If a mapping between compatible sexes existed such as in your example, it would be more useful to think of sex as continuous spectrum rather than a discrete collection.

Perhaps. But only because the mapping I've defined has so much symmetry.

Instead of the range [X-25 ... X+25], assign to each sex a random one of the 200-choose-50 (4.6 * 10^47) possible groups of partners sexes with size 50.

It would be impossible to completely describe the set of sexual compatibilities without simply enumerating them, and therefore necessary to treat the sexes as a set of discrete entities.

That's why I wrote "such as in your example."

I think that if each individual was randomly compatible with some subset of the population, we don't have 200 sexes, we have one sex and a 25% fertility rate.

A DNA sex is a set that can merge successfully with another set that produces an offspring. This is not always possible in all life because some sections of the DNA are incompatible when swapped.

Here is the sparrow with four sexes: https://www.nature.com/news/the-sparrow-with-four-sexes-1.21...

Conversely, what we think of sex (the genitalia and dimorphism identification) may not even be defined specifically by genes sets, but by epigenetic/environmental responses.

Even though alligators have DNA sets that are swapped, they are largely physically sexed by temperature: https://en.wikipedia.org/wiki/Temperature-dependent_sex_dete...

It even has an advantage, as females without mates can sometimes spontaneously reproduce and have offspring that are both male and female: https://en.wikipedia.org/wiki/Parthenogenesis_in_squamata

This is about the model species Schizophyllum commune. I found the OP article left me wanting to know more. The wikipedia page for S. commune links to a fascinating, in-depth page by an enthusiast:

http://botit.botany.wisc.edu/toms_fungi/feb2000.html

Also, there's this database with more pretty pictures and some distilled information:

http://www.mykoweb.com/CAF/species/Schizophyllum_commune.htm...

I hadn't realize how unique some of the fungal genetic systems were!

My understanding is that the main reason for different sexes in Fungi is to figure out whose mitochondria go on to populate the child after the nuclear DNA is combined. Having mixed populations of mitochondria inside a cell would provide an incentive for competition among them, which would be a Bad Thing. Otherwise they fungi could just do away with sexes entirely for a further, much smaller, increase in the number of potential partners.

See Power, Sex, Suicide: Mitochondria and the Meaning of Life by Nick Lane.

It strikes me as oddly cool for a fungus to find a cryptographic solution for their mating. And they still preserve some definition of a "collision".

You mean roughly: fused_hyphae = (A+B) ^ (C+D)?

I laughed for an unreasonably long time at "it must make for a wild singles night"

OT: The Joe Rogan podcast recently had Paul Stamets on who talks at great length about fungi and it's benefits -- truly fascinating stuff.

https://www.youtube.com/watch?v=mPqWstVnRjQ

That segment about how the fungi slime reorganized the Tokyo Subway System into a more efficient system was fascinating. Curious whether you could use this in someway to design everything from Circuit Boards to Software. One of my favorites so far.

The writing style is horrible.

Q: There are lots of techniques to preserve genetic diversity in EA/GA, like e.g. niching. Does anyone know if this specific thing has ever been tried?

Could you elaborate what EA and GA stand for the uninformed but curious, like me?

Evolutionary algorithms/genetic algorithms (https://en.wikipedia.org/wiki/Genetic_algorithm)

Thanks for hopping in while I was offline! (upvote)

The site has malware, to be precise it pops up an ad which says your Android is infected

Alternative link: https://www.popsci.com/fungi-sex

Well the Discovermagazine article at least gets right that this is about genetic diversity. The writer for Popsci butchers that into sexual diversity.

Being gay would be especially challenging for that species.

I'm sure there's plenty of bicelium.

Fungus Tumblr must support a lot of tags.

The best of all possible worlds is a free-form text entry.

Imagine how complicated the "about me" pages for OK Fungus are.

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