Even acknowledging the basic fact that males have more diverse expression is touchy these days on its own, I find; possibly because people are upset that men and women won't simply be hammered into the same form.
> The simple answer comes down to the fact that a species has to find a balance between maintaining genetic diversity, which is important for resilience and adaptation, and maintaining a strong breeding population.
> the basic fact that males have more diverse expression
Not to be a jerk, but you guys are just throwing out this stuff without backing it up and it's not at all self-evident to me. How are males more diverse?
Kind of feels like a big reason why this stuff is touchy is cause we're just saying things without having evidence for it, so yeah, there's not a lot of common ground to discuss.
[1] https://www.genome.gov/about-genomics/fact-sheets/Y-Chromoso...
The level of bias isn’t even solely dependent on the gene in question but on much more complex mechanisms that are frankly not well understood for example in humans testicles and mammary glands have some of the highest levels of sex biased expression in of all tissues. Other tissues like brain, heart and muscles also have variance but to overall lower levels (higher brain tissue expression variance in males for example has been linked to higher likelihood of schizophrenia and other mental conditions).
Overall males it seems that there is a higher variances of sex biased gene expression in various tissues compared to females.
This means that it goes beyond we have a backup X chromosome and gene deactivation escape mechanisms.
Gene expression variance can explain why males might a higher overall variance in traits.
In fact in males there is a phenomenon that is called feminization of gene expression where by removing sexual competition causes gene feminization in males causing the population to more favorably express female bias.
https://www.nature.com/articles/ncomms4482
I can’t find the study now but similar results have been reported in humans especially in sperm and testicular tissue that begin experiencing gene expression feminization rather quickly in monogamous relationships.
Coincidentally when searching to make sure I wasn't saying this the wrong way around, I was presented with this weird sexist propaganda[0] that only works because of the weird way people tend to think about these facts: you only acknowledge it if you can make it sound like women are better at everything and make no tradeoffs.
[0]: https://www.theguardian.com/books/2020/apr/19/the-better-hal...
To focus on one particular subset of this, recent research seems to indicate pretty conclusively that there is greater variability of (certain aspects of) intelligence among men than among women.
The reasons for this are poorly understood.
Is it genetic differences? Are boys and girls encouraged to investigate different things? Is it a limitation of our testing methods?
We aren't entirely sure yet so it's hard for people on either side to claim any complete understanding or provide a definitive answer.
https://en.m.wikipedia.org/wiki/Variability_hypothesis
While it's difficult, I feel all sides should be willing to research and discuss these differences without resulting to pearl clutching.
I appreciate you providing that information, really.
I'm sure you can google the IQ variance stuff.
I'm also willing to bet the height distribution, libido, interest in hobbies, single-mindedness vary a lot more in males than in females.
Politically correctness aside, wouldn't it make perfect sense that the sex that produces more gametes in a day than whole countries of opposite sex in their entire lifetimes would be the sex with more variance in any kind of feature because the potential rewards for taking a genetic risk could also pay a lot more than for the other sex?
I had heard this as a kid, but I haven’t seen anything to back it up recently that didn’t turn out to be wishful thinking by the author/reposter.
> wouldn't it make perfect sense that the sex that produces more gametes in a day than whole countries of opposite sex in their entire lifetimes would be the sex with more variance in any kind of feature because the potential rewards for taking a genetic risk could also pay a lot more than for the other sex?
I don’t see why the number of gametes is relevant, as the average number of viable offspring is necessarily the same.
This should hold for males, and I can see it making the number of gametes relevant. Historically, 80% of women and 40% of men have reproduced. In terms of reproduction, a woman could have maybe 20 children if they usually had twins or something. If a male wins big, like Genghis Khan, they might literally manage thousands.
I mean, it really doesn't seem like a stretch to see different selection pressures on males and the Y chromosome.
https://largescaleassessmentsineducation.springeropen.com/ar...
I would look at all the studies listed, rather than a summary written by the wikipedia editor.
But, this sort of disclaimer is not being equally applied because it would apply all psychology and sociology research. We have a few examples of research that shows just how extreme the social impact can be, but we don't understand impact enough to account for it.
Is it good science if the standards research are held to are not consistent depending upon the topic?
>Is it good science if the standards research are held to are not consistent depending upon the topic?
Passing a single standard would be a start.
Biologically, there are usually a complex history of reasons for an exhibited trait. It's important to remember tha sperm carry either a Y OR X gene expression, which inherently leads to more variability.
Human ovum undergo some mixing (https://genetics.thetech.org/ask-a-geneticist/odds-making-id...) but Human sperm are both more varied and larger quantity since they are more complex. The sperm both have to compete with each other and be acceptable by the ovum. -https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4071627/ (etc)
The actual payload of the sperm and ovum are roughly the same at ~8 million combinations for 8x8 million combinations for the fertilized ovum. -https://www.biology.iupui.edu/biocourses/N100H/ch9meiosis.ht...
So, the question implied by your casual comment is, what is the purpose of the multitude of sperm?
Is a multitude of sperm an evolutionary dead end (inefficiency)? Maybe, but there's no going back. The sperm faces quite a bit of natural resistance along it's fertilization journey. It's necessary, probably along the lines of the morphologically convoluted duck penises.
Is a multitude of sperm otherwise useful? Yes. It ensures a limit to the number of variations that can be passed on. If there are too many variations maybe the flagella will not be as efficient and loses to competition. -https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4242561/
Doss this directly contradict the idea of males having more variability? (posed by the previous paper). No. There are also environmental conditions (including seminal fluid involvement), temperature and the male/female bodies. Ovum are subjected to and less affected by environment than sperm, which likely is the source of greater variation overall. -https://jeb.biologists.org/content/218/1/107
There is also the nature of the disposability of sperm and the likelihood that there is less strict quality control, for a lack of better term, since competition solves inefficiencies on production quality. I could find nothing that indicates that this is a specific topic of study.
Rather, I am asking why to expect the number of gametes to be more relevant than the number of viable offspring when considering genetic diversity.
Exactly three of the $big_num of sperm my father’s body created led to offspring. Likewise exactly three of my mother’s eggs. Gamete_father >> Gamete_mother is true, but does not appear important in this specific regard.
I accept the other reasons you give for there being lots of sperm cells, but it’s answering a different question :)
Also the expression of neuro-diversity is usually more severe (do not have a linke for that one).
While we are at it, can we talk about the loop deformation, too?
Aka, evolution as a blind machinery, adapting humanity to the cycle of strife, by allowing neuro-diverse speacilizations to exist, which in turn try to propagate the circumstances they thrive in.
Thanks to science, we had a nice 90 years of surplus and plenty, basically bribing ourselves out of natures grasp. Now the whole messy affair returns with a vengance, and it will be interesting to see, if leviathan-cybernetics ( aka societal implants (cellphones, self-surveilance etc.)) can reign the forces of the old world in, were wishfull thinking and society regulation mechanisms (religions, rules, etc.)fail.
Most of the pictures of human females I see on the internet look the same. Young, nubile, thin, light-skinned, teased hair, painted like a clown, and where visible, completely devoid of body hair.
Perhaps observation bias is at play?
If you go to actual scientific literature, it's surprising how much everybody knows to be true is complete and utter billshut.
Well as for "you guys", I don't know this guy, I'm just adding my two cents to this dollar. As for it being self-evident: of course it's not self-evident, that's why it's a matter for scientific research. Your answers will be found searching for literature, not impugning the motives of random strangers on Hacker News.