Human sperm cooperate on the competitive pathway to fertilization: study

https://nautil.us/what-you-dont-know-about-sperm-482001/

by dnetesn • 3 years ago

168 102 3 years ago

nautil.us

stevenjgarner• 3 years ago

Time for Robin Baker to update the seminal "Sperm Wars" [1]

[1] https://en.wikipedia.org/wiki/Sperm_Wars

astura• 3 years ago

seminal

I see what you did there.

kridsdale14• 3 years ago

Let’s do a seminar on it this semester in the seminary.

throwawaaarrgh• 3 years ago

In certain bee species, the male’s body literally explodes after copulation, due to a sudden increase in intra-abdominal pressure, which embeds part of the now-deceased male’s body into the female’s genital tract, preventing other males from copulating with the just-fertilized female.

Wrong; other males can still mate with the female. The whole point is for her to mate with multiple males. I wonder what else in this story is incorrect

not2b• 3 years ago

It says "in certain bee species". Are you an expert in the field? You seem very confident here that this doesn't apply to any bee species.

CoastalCoder• 3 years ago

A citation might help your argument.

scarmig• 3 years ago

Since I was curious too, I dug up this:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1847503/#:~:tex...

Multiple males do mate with the queen, with the everted endophallus acting as a signal to other males and perhaps offering protection from the queen's stinger. Technical term seems to be "mating sign," and males prefer queens with a mating sign.

SoftTalker• 3 years ago

I can think of worse ways to die than a fatal orgasm.

because_789• 3 years ago

About one-fifth of mammalian (including human) sperm are typically abnormal, containing no heads, two heads, two or more tails, oddly misshapen or malfunctioning tails, and so forth.

TIL

kridsdale14• 3 years ago

For myself, it was something like 94% misshapen. The fertility doc told me not to worry.

Indeed it was not an impediment.

TecoAndJix2• 3 years ago

You can get a microscope on Amazon for a few hundred bucks that lets you see this, red blood cells, and the critters that live in the water behind your house. Fun way to spend a weekend!

_zoltan_• 3 years ago

any specific recommendations that one could hook up to something to record the images/video?

AuryGlenz2• 3 years ago

When we were dealing with fertility issues I started doing (somewhat) legit sperm counts at home. I was sick of paying hundreds of dollars each time.

I’m sure it wasn’t super accurate but it was accurate enough to know if things were improving on certain medications or not.

pfannkuchen2• 3 years ago

Isn’t the purpose whole “sperm race to the egg” thing to QA the sperm? Slow or immobile sperm is a proxy for manufacturing defects (which could affect the genetic material within, I suppose).

ihalip• 3 years ago

Wait until you realize almost four-fifths are dead, immotile or slow moving. Only around 5% are actually viable.

__MatrixMan__4• 3 years ago

Animals' shared ancestor with fungus is thought to be among https://en.m.wikipedia.org/wiki/Choanoflagellate, which kinda look like sperm.

My guess is that they were predominantly haploid (like sperm/eggs), and just had a diploid (like most other human cells) phase for reproduction. Somewhere along the way this switched (which is thought to have happened in plants also, mosses are primarily haploid while flowering plants are primarily diploid).

...which is totally bonkers. It's like if sperm/eggs went around making all of the important decisions and only bothered to spin up a human briefly for reproductive purposes. But then the sex got a bit out of control and got a job and an apartment and now it's the sperm who look like they're just for reproduction.

Disclaimer: I took Bio 101 two semesters back, so I'm pretty much an expert.

kridsdale14• 3 years ago

Your comment reminds me of another biology tale:

The natural, most efficient, and optimal state of an animal is napping.

Wakefulness, and everything that happens during that time, is just an annoying distraction to maintain homeostasis.

throwup2382• 3 years ago

That is the natural state of the domesticated cat because we have artificially selected them to match our aspirations. The optimal nappers. They’re awake just long enough to remind us that they’re the boss and our sole function is to feed them.

EarthLaunch• 3 years ago

It's like if *humans* went around making all of the important decisions and only bothered to spin up a *machine* briefly for reproductive purposes. But then the sex *bot* got a bit out of control and got a job and an apartment and now it's the humans who look like they're just for reproduction.

This perspective could kind of also apply to plants, a la The Botany of Desire (good book). From a certain plant's perspective, humans exist to help them reproduce.

layer8• 3 years ago

You can go even further: https://en.wikipedia.org/wiki/Gene-centered_view_of_evolutio...

__MatrixMan__4• 3 years ago

I subscribe to that view, but I don't think it's any more wild than https://en.wikipedia.org/wiki/Alternation_of_generations

Sure, it's the genes that are doing all of this, but the fact that they would chose two totally separate body plans, each which is a reproductive system for the other... It just seems a bit too scifi to be real.

wahern• 3 years ago

It's like if sperm/eggs went around making all of the important decisions and only bothered to spin up a human briefly for reproductive purposes.

That's very close to the thesis of Richard Dawkins' seminal book, the Selfish Gene--we're just machines constructed by genes to replicate them. It's literally true, of course, but we don't often take that perspective; yet many things in biology aren't intuitive unless and until we do.[1]

[1] OTOH, some things in biology become inexplicable when we do take that perspective, such as non-kin altruism. IIRC, Dawkins admits as much in the book. (Contra some subsequent sociopolitical interpretations, Dawkins never used his "selfish gene" model to refute the possibility of non-kin altruism, just that the model in isolation was insufficient to explain non-kin altruism, the existence of which he seemed to take for granted, at least in humans.)

skolskoly• 3 years ago

seminal book

Don't think that we don't see this.

mewpmewp2• 3 years ago

Isn't non kin altruism just prisoners dilemma part of the evolution? E.g. groups that work together will survive and genes of these groups will get passed on. So the desire is to help any friendly individuals, but it also works globally because this hasn't really even been part of evolution to be so globalized.

wegfawefgawefg• 3 years ago

non-kin altruism could just be a mistake. A behaviour intended to be applied to ones own species, but ends up applied to others because of the detectors used to identify another agent not being scrutinous enough.

Just because you get diabetes doesnt mean its the intended behaviour of evolution. Could be a spandrel, or an artifact, or aliasing, or a plain mistake.

anigbrowl• 3 years ago

I'm something of a scientist myself*, and every time I delve into cellular biology I find myself wondering if there is a primitive consciousness on the cellular level, because lives of many cells are complicated.

Consider Memory B cells, which are formed early during foetal development. They hang around in the body for years - sometimes decades - looking out for new and unusual pathogens. When they encounter one, they internalize the peptides and then (typically, but not always) rush off to a germinal center to help manufacture new T cells that can recognize and defeat the unwanted interloper. then the B cells leave again and go back to their vigil.

https://en.wikipedia.org/wiki/Memory_B_cell

Conversely, when you look at the dynamics of large groups, organizations, and corporate entities (institutions as well as business, up to whole nations), it's hard not to see them as organisms in their own right that have a sort of meta-consciousness independent of their component humans.

* This is a joke

__MatrixMan__4• 3 years ago

I have that thought quite often, both for cells and for aggregate things like countries or religions.

Most recently I found myself framing zoonotic diseases (e.g. Lyme, Covid, Malaria) as ecosystem-level weapons against habitat loss i.e. as a manufactured reason to keep humans away.

asylteltine• 3 years ago

Isn’t another explanation that they travel in such large amounts they will eventually interact with the right system due to chemical interactions? That is the right proteins will activate the right channels eventually when you have hundreds of thousands of attempts? I don’t think they are conscious in the sense they are driving along a road and know where to turn. It’s all chemical signaling and statistics.

tracerbulletx• 3 years ago

You might like the book Transformer: The Deep Chemistry of Life and Death by Nick Lane. (anyone enjoying this comment section would) but specifically he presents some really cool interesting ideas related to this and metabolism

sirspacey• 3 years ago

A joke from one of the greatest Spider-Man movies of all time, so you get a pass

Wherecombinator• 3 years ago

I can’t remember where I’ve seen it but there’s some interesting work done Michael Levin in this space. Something along the lines of how cells alone can have a goal but within a group exhibit different goals. This can go from cell to tissue to organ, all the way up to society. I’m not a biologist so I’m butchering his ideas, just writing this if anyone finds it interesting to look him up.

JumpCrisscross• 3 years ago

I find myself wondering if there is a primitive consciousness on the cellular level

Has anyone seriously tried tackling this with fiction?

galaxyLogic7• 3 years ago

Right cells of a single individual co-operate, why should sperm-cells be any different.

brabel2• 3 years ago

I find myself wondering if there is a primitive consciousness on the cellular level

That seems to be obviously true to me. The alternative would be that consciousness simply appears at some point out of literally nowhere because there would be no lower levels from which it emerges.

indigoabstract• 3 years ago

Conversely, when you look at the dynamics of large groups, organizations, and corporate entities (institutions as well as business, up to whole nations), it's hard not to see them as organisms in their own right that have a sort of meta-consciousness independent of their component humans.

That's actually a thing, or at least there's a name for it:

https://en.wikipedia.org/wiki/Egregore

b4ke2• 3 years ago

This struck me like a Medicare benefits review commercial. I think those are also a bit more substantive. ;)

edgyquant2• 3 years ago

I don’t think there’s a consciousness but I think most biologist would agree there must be some kind of “awareness” within cells and imo likely that awareness is the basis for what we’d call consciousness.

a_gnostic2• 3 years ago

I heard sex exists to reshuffle genes to make it difficult for parasites

__MatrixMan__4• 3 years ago

I guess if your offspring has an entirely different body plan than you and it's only their offspring that resembles you then it would take a very clever parasite indeed to complete the cycle and follow the germ line across both transitions.

AndrewKemendo2• 3 years ago

I read a book long ago called Sperm Wars. It’s almost pornographic in style but every chapter describing the biology of sperm and sex is preceded with a fictional narrative of some courting ritual.

Really blew my mind at the time at how complex and interconnected the behavior of sperm and egg are with general human behaviors via hormone communication.

kridsdale14• 3 years ago

You should also read Dawkin’s The Selfish Gene.

Everything we think we are, and what we are here to do, is fight to make our kids or our kin’s kids (if we can’t / won’t reproduce) survive and do the same.

Politics, architecture, everything is you being manipulated to do this.

AndrewKemendo2• 3 years ago

Oh yes that’s a great one too.

The general category of evolutionary biology humbles you quickly out of any notion that thinking you have anything resembling free will in most of your life.

trgn• 3 years ago

I think stepgen gould (?) joked that taking that perspective, you could easily argue that the purpose of the human organism was for shit to make more shit.

galaxyLogic7• 3 years ago

And "kin" basically means anybody or anything that contains SOME of the same DNA.

Qwertious• 3 years ago

Everything we think we are, and what we are here to do, is fight to make our kids or our kin’s kids (if we can’t / won’t reproduce) survive and do the same.

IIRC, the point is that this is not the case - that's what our genes "want", with manipulations like sex feeling good to get us to have children (but we fought back with contraception, and evolution is extremely slow to catch up).

giantg23• 3 years ago

Some of this might not be accurate.

"Human testes are on average 0.06 percent of body weight and sperm concentration is about 25 million per ejaculate."

25 million per ejaculation would fall in the "low" fertility category. At the other end of the range you can have 10x that amount.

The part about bee phallus implantation is true, but to my knowledge it does not really deter others (in honey bees at least). The queen mates with multiple males and has offspring using genetics from more than one.

AuryGlenz2• 3 years ago

25 million is quite low. ~15 million per ml is considered infertile and you usually ejaculate at least 1.5ml.

bee_rider• 3 years ago

The idea that sperm cooperate is quite funny. They are sometimes used as a sort of example of how wildly competitive life is from the very start, we were in cooperation to even be born. In fact, it was a group project.

gumballindie• 3 years ago

example of how wildly competitive life is from the very start

Isnt sperm more like data rather than a living thing? Nonetheless, without cooperation, humans, would not have survived. It is only logical that our initial data carriers also cooperate in some way.

galaxyLogic7• 3 years ago

Yes, they are about security by redundancy, and randomization. Every child you have is different and therefore more able to survive as circumstances change.

Qem• 3 years ago

If sperm cooperate, I wonder if the effects of the reported[1] historical decreasing sperm counts are worse than thought. For example, if the value drops by half, perhaps the decrease in fertility is not linear, but quadratic, falling to 1/4 of the original value, because each of the 50% left has only half the average number of peers to cooperate (this is only an example. I have no idea on how fertility scales with sperm counts).

[1] https://www.amazon.com/Count-Down-Threatening-Reproductive-D...

munchler• 3 years ago

When sperm disband their cooperativeness, it’s each pollywog for himself.

I'm surprised to see Nautilus implying that all sperm are male. Half of those pollywogs carry an X chromosome. You go, girls!

galaxyLogic7• 3 years ago

That's because sperm-cells of a single male all share the same goal. They are not really competing are they? They all have the same goal, carrying on the genes of the same individual.

justinl33• 3 years ago

This pattern is consistent with data on the average number of male sex partners for females per birth: gorillas, one partner per birth; human beings, 1.1; baboons, 8; bonobos, 9; and common chimps, 13.

I don't understand this statistic. 'Human beings average 1.1 male sex partners per birth...' we need to see the data behind this. This isn't implying that 1 in every 11 children are bastards, no?

subarctic• 3 years ago

That number (1.1) seems low, considering the average number of lifetime sex partners for women is something like 5 or 6 and the average number of births (fertility rate) is something like 2. How can we track down the source for that statistic and figure out how it was measured?

ljlolel• 3 years ago

This is one of the reasons that 23andme has warnings about dna matching to relatives

https://theconversation.com/what-are-the-chances-that-your-d...

claviska• 3 years ago

When the hard-working little swimmers encounter the thicker vaginal mucus, their path is slowed. So the sperm often join together at their heads, which gives them greater swimming speed (up to 50 percent faster) than if they were to carry on individually.

Teamwork makes the cream work.

fallingfrog• 3 years ago

Well, they do all have pretty much the same dna, so it makes sense I suppose. The same way that ants cooperate.

Human sperm cooperate on the competitive pathway to fertilization: study

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