Why Sex? Biologists Find New Explanations • Hacker News Board

Re: Why Sex? Biologists Find New Explanations

#91

Post by ben_w » Fri, Apr 24, 2020, 9:38 PM UTC

Supermancho wrote: post #83

ben_w wrote: post #14

Earlier quoted context omitted.

> Isn't it a common known fact that while average IQ is the same for males and females, male IQ varies more and hence there are more male idiots as well as more male geniuses? 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 count…

> I don’t see why the number of gametes is relevant, as the average number of viable offspring is necessarily the same. 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..…

> So, the question implied by your casual comment is, what is the purpose of the multitude of sperm?

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 :)

Re: Why Sex? Biologists Find New Explanations

#92

Post by throwaway6575 » Fri, Apr 24, 2020, 9:40 PM UTC

globular-toast wrote: post #81

throwaway6575 wrote: post #59

Earlier quoted context omitted.

Lol I've heard so many times about the conspiracy of biologists who are afraid to "tell the truth" about sex differences. Everyone is like Damore, cowing in front of the SJW crowd and afraid to be fired4truth. The reality is much more tame. The crux of the matter (and potential controversy) is not about sex differences in plants or C. elegans. Most biologists I've met who study algae or polar bears usually limit thei…

Who said anything about humans? My original comment certainly didn't.

I don't know what you're talking about then. But plenty of comments in this thread did.

Re: Why Sex? Biologists Find New Explanations

#93

Post by throwaway6575 » Fri, Apr 24, 2020, 9:45 PM UTC

globular-toast wrote: post #82

throwaway6575 wrote: post #59

Earlier quoted context omitted.

Lol I've heard so many times about the conspiracy of biologists who are afraid to "tell the truth" about sex differences. Everyone is like Damore, cowing in front of the SJW crowd and afraid to be fired4truth. The reality is much more tame. The crux of the matter (and potential controversy) is not about sex differences in plants or C. elegans. Most biologists I've met who study algae or polar bears usually limit thei…

I don't think you know what a conspiracy is. People don't speak up precisely because they are alone and don't want to be shunned by the echo chamber. If you've heard about it so many times, why do you think you know best and deny the observations of others?

I also happen to work with biologists and I found no such thing as you describe. People aren't afraid to talk about sex differences. There's no hidden truth that everyone speaks in undertones about and is scared of mouthing out loud. People don't mindlessly transpose what they know about their model organisms to humans. People don't buy into evopsych crap either. (There's a reason evopsych papers have trouble even making it into PNAS.) The community isn't filled with Damores either. So maybe you could clarify what you're talking about because I seem to have lost you there.

Re: Why Sex? Biologists Find New Explanations

#94

Post by reubenswartz » Fri, Apr 24, 2020, 9:55 PM UTC

koeng wrote: post #75

reubenswartz wrote: post #65

I'm not a biologist, but my understanding is that bacteria are much more likely to undergo horizontal gene transfer when undress stress. (Particularly troubling these days for antibiotic resistance.) Seems like it would be a natural next step for single cell eukaryotes to have a similar mechanism to fix bad DNA, especially given the much longer genomes of eukaryotes, which the article discusses without mentioning bac…

Eukaryotes don’t really evolve very much on the protein level - their complexity allows them to mostly evolve on the regulatory level (while bacteria often still are on the protein level). Practically, this means that getting proteins from elsewhere isn’t that selected for, while better regulation is. It’s a complicated subject, but that’s partially why there is so much “junk” dna in multicellular eukaryotes (single…

My primitive understanding is that the bottleneck for bacterial reproduction is DNA replication, so there’s a huge incentive to shed unneeded DNA, especially with mechanisms to get genes back via HGT. Am I right in thinking that the more efficient chromosome replication in eukaryotes doesn’t penalize junk dna the same way, so it can just stick around?

Re: Why Sex? Biologists Find New Explanations

#95

Post by vikramkr » Fri, Apr 24, 2020, 10:42 PM UTC

throwaway6575 wrote: post #90

luckylion wrote: post #79

Earlier quoted context omitted.

> "most of what works in other species doesn't work in humans" (see: 99% of drug trials) Isn't the point of doing animal trials that they are "close enough" for most things to deliver good results? I.e. "if you can't do it in mice, dogs and pigs with your proposed medication, you probably won't be able to do it in humans". They're close enough that xenotransplantation is actively considered. "Humans are so special, e…

"It works in a close animal" is a necessary though far from sufficient condition for "it" working in humans. The point of doing animal trials is to filter out drugs that don't even fulfill that condition. Look at the "in mice" twitter account. How many potential Alzheimer treatments and cures for cancer have been touted in the last decade that proved effective in mice? How many of them turned out to be promising in h…

One thing to consider is that with the alzheimers trials, the mice might be so different that what works in humans might not work in mice. We dont yet have the tools and infrastructure to deal with that hypothetical, though there is some promising work with lab on a chip and brain organoids that could solve that sort of problem of it turns out to be the case

Re: Why Sex? Biologists Find New Explanations

#96

Post by vikramkr » Fri, Apr 24, 2020, 10:46 PM UTC

philipkglass wrote: post #86

luckylion wrote: post #79

Earlier quoted context omitted.

> "most of what works in other species doesn't work in humans" (see: 99% of drug trials) Isn't the point of doing animal trials that they are "close enough" for most things to deliver good results? I.e. "if you can't do it in mice, dogs and pigs with your proposed medication, you probably won't be able to do it in humans". They're close enough that xenotransplantation is actively considered. "Humans are so special, e…

We haven't found anything better to replace animal trials yet, but they aren't close enough to deliver good results. Animal trials precede the first (Phase I) clinical trials in people. 93% of drugs that make it past animal trials and into Phase I clinical trials fail to make it all the way to final approval: https://blogs.sciencemag.org/pipeline/archives/2019/05/09/th... It's also not clear how many drug candiates w…

In terms of false positives, the story of Guinea pigs and penicillin comes to mind. IIRC Guinea pigs were more susceptible (might have been that their gut microflora leaned gram positive and that led to toxic effects after penicillin administration? Dont recall exactly off the top of my head).

Re: Why Sex? Biologists Find New Explanations

#97

Post by 205guy » Sat, Apr 25, 2020, 12:01 AM UTC

hammock wrote: post #36

Zaak wrote: post #35

Earlier quoted context omitted.

> is meiosis and mitosis the only two way to reproduce? Well, from a high-level view the only way a cell can make more cells is to divide, and if it divides it either makes a copy of its genetic material first, or gives half of it to each daughter cell. So in that sense, they're the only two ways possible. From a more detailed view, I wonder if the machinery of meiosis is evolutionarily the same in every sexually-rep…

>Well, from a high-level view the only way a cell can make more cells is to divide, and if it divides it either makes a copy of its genetic material first, or gives half of it to each daughter cell. So in that sense, they're the only two ways possible. Ignoring the idea of three-way (or more) genetic swaps, which would be like another type of meiosis, what if there were other ways? What if there was a "carbon copy" o…

Isn't that what we call a "virus"?

Re: Why Sex? Biologists Find New Explanations

#98

Post by limomium » Sat, Apr 25, 2020, 3:58 AM UTC

Supermancho wrote: post #89

sdenton4 wrote: post #84

Earlier quoted context omitted.

I /think/ they're saying that if sexual reproduction came first, you have a pretty basic problem: where's the second individual that the first sexually reproducing entity mates with?

Sexual reproduction can involve an asexual (which would be hemaphroditic) partner.

Why would you evolve the necessary organs to sexually reproduce with your self, with no one else around?

Re: Why Sex? Biologists Find New Explanations

#99

Post by jmeister » Sat, Apr 25, 2020, 4:50 AM UTC

econcon wrote: post #66

If same sex attraction exists biologically, not as a social construct than it's possible those genes are select as side effect of smth else that comes with it. For example, my gay friend is godlike attractive and one girl literally begged him to marry him in really sick ways and he's ended up marrying her to make his life easier and also because she was completely attached and attracted to us just because of how he l…

Wow can we see a picture of this Adonis please?

Re: Why Sex? Biologists Find New Explanations

#100

Post by dogma1138 » Sat, Apr 25, 2020, 10:11 AM UTC

nootropicat wrote: post #30

dogma1138 wrote: post #17

Earlier quoted context omitted.

This isn’t about sex chromosomes, we have 1000’s of genes that are sex-biased this means that their expression is dependent on sex. 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…

The existence of those mechanisms doesn't mean the increased variance from only one X chromosome disappears - for males to have equal variance the increase from just one X would have to be compensated somehow, which is probably impossible given how directly important X is - the needed information is gone.

What I’m saying is that genetic variance and gene expression variance aren’t the same thing.

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.