[HN Gopher] How the placenta evolved from an ancient virus (2020)
       ___________________________________________________________________
        
       How the placenta evolved from an ancient virus (2020)
        
       Author : bkudria
       Score  : 108 points
       Date   : 2024-01-20 21:43 UTC (1 days ago)
        
 (HTM) web link (whyy.org)
 (TXT) w3m dump (whyy.org)
        
       | dang wrote:
       | Related:
       | 
       |  _How the placenta evolved from an ancient virus_ -
       | https://news.ycombinator.com/item?id=25655346 - Jan 2021 (106
       | comments)
        
       | ta8645 wrote:
       | It's a little odd to consider the idea that fighting off modern
       | viruses today, might actually be impeding human evolution in some
       | way we can't foresee.
        
         | AdmiralAsshat wrote:
         | I suppose the ethical question would be: how many current
         | humans are you willing to let die from exposure to a virus in
         | the hopes that one of them might mutate something useful?
        
           | ta8645 wrote:
           | It's really an impossible calculation. There's no way to
           | appraise the consequences to assign a value. If it were
           | possible to say, that a future mutation was necessary to save
           | humanity (ie. we are doomed without entering that future)
           | well then perhaps we'd be willing to sacrifice a lot of us
           | now.
           | 
           | It's all academic of course, we'll never make such a
           | decision, and never know what could have been. It's just
           | another reminder that we don't really know the future or the
           | best course of action in these situations -- we're just
           | taking our best guess (even the experts).
        
             | omeid2 wrote:
             | > a future mutation was necessary to save humanity
             | 
             | Even in that scenario, it is very simple, we protected the
             | people today and use vaccines to induce the necessary
             | mutation. The moral choice in my book is to always err on
             | the side of the living than "potential of the living".
        
               | ta8645 wrote:
               | That's your personal calculus, and fair enough. World
               | leaders might make a different decision though.
               | 
               | For instance, the British military planners allowed
               | soldiers to die on the battlefield, who they could have
               | saved, in order to protect the secret that they had
               | cracked German encryption during WWII. That was a place
               | where the needs of the many, were deemed more valuable
               | than the lives of the few.
               | 
               | I'm not judging one way or the other, but it has happened
               | in human history more than once. And in the imaginary
               | scenario where leaders had perfect knowledge of the
               | future, it would likely happen again.
        
               | vlovich123 wrote:
               | That isn't as hypothetical a situation though as what you
               | outline which is preventing a mutation now that may be
               | important tens, hundreds of thousands of years or maybe
               | even millions from now. There's so much time for
               | technology to evolve to make it likely that any negative
               | effects can be countered through that as technology can
               | deal with problems on a much shorter time scale than
               | evolution can.
        
               | omeid2 wrote:
               | > For instance, the British military planners allowed
               | soldiers to die on the battlefield, who they could have
               | saved, in order to protect the secret that they had
               | cracked German encryption during WWII. That was a place
               | where the needs of the many, were deemed more valuable
               | than the lives of the few.
               | 
               | This is not a very good comparison, in my opinion.
               | Military is rarely about the "needs of the many" far more
               | than it is about the "powers that be". Once you
               | understand the dynamic at a play, it is rather clear that
               | the soldiers died for what soldiers _almost_ always die
               | for; the regimes that pushes them to war.
        
             | romusha wrote:
             | That's the domain of longscamism
        
         | boredgargoyle wrote:
         | There are probably thousands (and my guess would be much more)
         | viruses that that dance on the information playground that is
         | our genome, metagenome, and the genomes of the organisms we
         | host. Fighting a few of them is probably not going to be a
         | significant issue.
         | 
         | Having more individuals around by itself would also lead to
         | mutations which the environment may select for in the future.
         | By itself there is no such thing as a beneficial mutation (gene
         | import) unless the environment proves it to be.
        
           | ta8645 wrote:
           | You're really missing the point -- there's no way to know the
           | future. Maybe your optimism is warranted, but maybe we
           | stamped out a virus that would have given us a superpower.
           | 
           | The argument is _not_ that we should change our strategy of
           | doing the best we can with the information we have. Just that
           | we should have some humility about what we can and can't
           | actually predict, or say with certainty.
        
             | vlovich123 wrote:
             | Our superpower is developing technology. It's unlikely
             | evolution could ever outperform that as it operates on much
             | slower time scales for adaptation. So any viral mutation
             | now will only really manifest at population scale after
             | hundreds of thousands of years whereas technology can do it
             | within years or decades.
        
               | ta8645 wrote:
               | You're doing a lot of work to continue to miss the point.
               | The point is not that we should embrace viruses in order
               | to reap the benefits. Just that it is _POSSIBLE_ that a
               | virus would turn out to be very beneficial to humanity,
               | in the long run. We know this to be a fact, because of
               | the article we're reading above.
               | 
               | The only point I'm hoping people will take, is that we
               | shouldn't be so quick to make categorical statements
               | about the future; like we know exactly how things will
               | play out. I don't know for sure. You don't know for sure.
               | The experts don't know for sure.
        
               | vlovich123 wrote:
               | No, you're assuming a counterfactual that isn't
               | necessarily true. If the virus hadn't come along,
               | humanity as it stands today may not exist but whatever
               | animal was infected could potentially have kept
               | reproducing / another virus would accomplish what
               | happened anyway. Those are far more likely scenarios.
               | 
               | You're taking an impossible to prove hypothetical that
               | would require omniscient level reasoning and predictive
               | powers to prove or disprove - it's not a productive line
               | of reasoning and you're falling into the exact same trap
               | you're accusing others of doing. The WWII example is also
               | highly flawed because that one was experts making
               | strategically reasonable calls. Worrying about some
               | hypothetical virus that in the distant future is critical
               | is not strategically reasonable - it's science fantasy.
        
               | ta8645 wrote:
               | > No, you're assuming a counterfactual.
               | 
               | I'm not assuming anything. I'm following the science as
               | reported in the article above. That in FACT a virus lead
               | to an important part of human development. And was in
               | FACT beneficial. Those are true facts, if you trust the
               | science.
               | 
               | > If the virus hadn't come along, humanity as it stands
               | today may not exist but whatever animal was infected
               | could potentially have kept reproducing / another virus
               | would accomplish what happened anyway. Those are far more
               | likely scenarios.
               | 
               | You literally immediately launched into assuming a
               | counterfactual (that didn't happen, you just made it up).
               | 
               | > You're taking an impossible to prove hypothetical that
               | would require omniscient level reasoning
               | 
               | Yes, and I made it clear that's what I was doing. And I
               | explicitly said it was an imaginary situation that would
               | never happen. I was using it for illustrative purposes
               | for people who are flexible enough in their thinking. I'm
               | sorry that isn't you.
        
               | qup wrote:
               | Additionally, the tech level will eventually allow us to
               | discover and implement any/all available superpowers.
        
             | theGnuMe wrote:
             | Super powers would be sensory I think unless we sprout
             | wings or gills. So things we've probably seen already in
             | another species like infrared vision or what not... but we
             | do have technology to do that already so the question is
             | how does that influence the evolutionary landscape.
        
         | pazimzadeh wrote:
         | Yeah, if I remember correctly the RAG recombinases that enable
         | crazy diversity in your B and T cell receptors of your adaptive
         | immune system are also thought to come from a retrovirus that
         | got into our ancestors germ cells.
        
         | badosu wrote:
         | It is required some process of natural selection for mutations
         | to be selected against, do we know how this occurs with the
         | modern homo sapiens?
        
           | MrVandemar wrote:
           | We have plenty of modern day selection pressure. Watch the
           | first 2 minutes of _Idiocracy_.
        
           | pfdietz wrote:
           | Unless you think our ancestral biology is perfectly adapted
           | to the modern world, evolution will be acting. Indeed,
           | evolution is probably occurring on humanity at a breakneck
           | pace right now, because our environment has changed so
           | radically.
        
         | juggertao wrote:
         | Umbrella Corporation is working on the innovative t-Virus for
         | the next step in human evolution. But people FUD it.
        
         | 6177c40f wrote:
         | I think the tradeoff is worth it, viruses are far more likely
         | to do us harm than to help us out. Besides, we're entering the
         | age when we can direct our own evolution.
        
       | chasil wrote:
       | One way that viral elements are expressed are as transposons.
       | 
       | There is even an infectious variant, a gypsy transposon, that can
       | move to neighboring cells.
       | 
       | https://en.m.wikipedia.org/wiki/Transposable_element
        
       | mlcrypto wrote:
       | Kinda morbid thinking about all the failed mutations as laying
       | eggs evolved into the placenta
        
         | jmyeet wrote:
         | Here's another sobering thought: you represent an unbroken
         | chain from the universal common ancestor of successful
         | reproduction going back billions of years and probably
         | trillions of generations (given that many of those were as a
         | single-celled organism). Every one of those generations a
         | success.
         | 
         | So if you fail to reproduce you will break that billion year
         | old chain of evolutionary success.
         | 
         | Here's another: you have 2 biological parents, (up to) 4
         | biological grandparents (go look at Cleopatra's family tree)
         | and so on to an upper bound of 2^n ancestors for the n'th
         | previous generation. At some point this number exceeds the
         | number of organisms that were alive at that time so there are
         | likely one or more individuals in the past who are direct
         | ancestors to everybody.
         | 
         | A consequence of this is that if you go forwards in time
         | ultimately your genetic line will either die out or you will be
         | the direct ancestor of everybody given sufficient time.
        
           | vlovich123 wrote:
           | Humans are social animals. It's myopic I think to only
           | evaluate based on reproduction and genetic propagation. For
           | example, most bees and ants are not involved in reproduction
           | but they are all involved in helping the species survive into
           | the future. So even if you don't reproduce you have a
           | critical role to play in society (helping it stay cohesive,
           | helping productivity, helping through your work efforts,
           | helping your friends and family raise children who can help
           | humanity survive and be good humans themselves etc)
        
             | mrphoebs wrote:
             | I doesn't seem like the above commenter was making a value
             | judgement.
        
               | vlovich123 wrote:
               | > So if you fail to reproduce you will break that billion
               | year old chain of evolutionary success.
               | 
               | I'm responding to this and saying that's not an accurate
               | way to frame it. I'm saying you are participating in
               | evolutionary success even if you don't reproduce. For
               | example, a more social family where there are siblings
               | that don't reproduce and instead invest in the success of
               | the reproductive sibling's offspring is still
               | evolutionary success and would be being selected for
               | through your whole families reproductive success as a
               | whole rather than your individual success.
               | 
               | The argument being made here is similar to the argument
               | that sterilizing would result in removal of genes from
               | the pool - it doesn't work because gene selection is very
               | complicated and doesn't solely rely on individual
               | reproduction.
        
               | mrphoebs wrote:
               | My mistake, I presumed incorrectly, that the argument you
               | were making came from a place of defensiveness, rather
               | than a more holistic framing of evolutionary success.
               | Thanks for providing further clarity.
        
               | dr_dshiv wrote:
               | I like this argument because it frames the "self"/"you"
               | as an illusion--instead, there is a more distributed
               | self. I recognize that there are arguments against this
               | argument -- but you point out that DNA identity is pretty
               | distributed as well. Neat.
        
               | NortySpock wrote:
               | I'm currently more focused on spreading good memes to the
               | next generation.
               | 
               | Memes like kindness, empathy, planning ahead, being
               | honest with yourself (and preferably others),
               | communicating your intentions clearly ahead of time, and
               | how good parenting takes more emotional labor and
               | emotional intelligence than, say, the kind of parenting
               | that solely consists of yelling when the parent does not
               | receive the desired response from the child.
               | 
               | Genes are not the only thing the next generation needs.
        
             | Loughla wrote:
             | Genetic line =/= role to play in society.
             | 
             | Those are different things.
        
             | lo_zamoyski wrote:
             | The OP was making an observation. But I'll bite.
             | 
             | First, human beings are not bees or ants. Our nature vis-a-
             | vis reproduction is quite different. Most human beings do
             | reproduce as that is our nature, or certainly most of us
             | used to with the exception of periods of social collapse
             | (think of Rome). We're in that sort of condition now, where
             | we are having little or no children in the developed world.
             | This does not bode well and at some point the decline of
             | such a society will become irreversible.
             | 
             | Of course, you are right that not everyone _must_
             | reproduce, that there is no particular obligation for
             | anyone to reproduce, and that those who do not can still
             | contribute to the well-being of their families, the human
             | species, and the common good. And indeed, if you are, say,
             | a Catholic, you would say that while having children is the
             | natural course and the normal path for most people, a small
             | minority are called to sacrifice this natural end for the
             | sake of a higher supernatural, spiritual end, e.g., the
             | priesthood, by which one becomes a spiritual parent in
             | place of a biological one. Certainly, we can be parental
             | figures in non-biological ways as well. Even biological
             | parents do that.
             | 
             | But that's not that we're seeing behind the present
             | demographic decline. Something like the priesthood is an
             | exception, not the rule. Most who can have children of
             | their own are not having them, or many of them, not because
             | of some kind of exceptional higher calling, but rather for
             | morally dubious reasons. Children are demanding. They
             | require sacrifice. They demand the love known as charity. A
             | consumerist is going to view a child not as a gift, but a
             | burden. Furthermore, our society demonizes families,
             | especially large families (perhaps in part stemming from
             | Protestant attempts to restrict Catholic populations in the
             | US). Having many children used to be seen as a blessing, a
             | privilege. Today, we both think we're _entitled_ to having
             | children (IVF is a testament to that), and refuse to have
             | them.
        
               | ARandomerDude wrote:
               | > Furthermore, our society demonizes families, especially
               | large families (perhaps in part stemming from Protestant
               | attempts to restrict Catholic populations in the US)
               | 
               | I think it has a lot more to do with feminism than any
               | Protestant/Catholic divide. In the Protestant church I
               | attend, having 6+ kids is pretty normal. Certainly many
               | evangelicals don't value large families but I think
               | they're getting that mindset from the culture, rather
               | than sacred Scipture.
        
               | zpeti wrote:
               | Some say feminism (and progressivism) is just an offshoot
               | of protestantism, albeit a secular, puritan version.
        
               | vlovich123 wrote:
               | No humans aren't bees or ants. We're social animals and
               | you can't ignore society and culture as aspects of
               | evolution.
               | 
               | Regardless, you've taken this whole thing in a weird
               | direction bringing up a demographic collapse that is a
               | fringe theory at the moment. As for that hypothesis,
               | there's no actual indication that humanity is in any
               | danger of a collapse just because the boomer generation
               | is passing and our numbers return to normal. Humans can
               | reproduce quite quick and have a long reproductive
               | lifecycle - if it ever becomes a problem society will
               | change to priority life more. As it is, life has gotten
               | pretty difficult in terms of supporting kids and people
               | having fewer is a symptom of that and not consumerism as
               | you claim. And children are both a blessing and a burden.
               | If they weren't a burden then the statistics about
               | teenager births and the outcome for the parents and
               | babies wouldn't be as bad as they are.
        
               | zpeti wrote:
               | > demographic collapse that is a fringe theory at the
               | moment
               | 
               | Show me the actual numbers where this isn't a massive
               | change in humanity in the future?
               | 
               | This is not a fringe theory. The effects of the collapse
               | we can theorise on, but the collapse will happen now.
               | It's not a question or a theory.
        
               | InSteady wrote:
               | I mean, population decline is a thing, and most
               | 'developed' nations, or whatever you want to call us, are
               | experiencing it. Demographic collapse sounds like a a
               | scary term bandied about by people with an agenda (or
               | those who want to proclaim the sky is falling but
               | bizarrely want to ignore climate change and ecological
               | collapse).
               | 
               | I'm just guessing, because I haven't encountered the term
               | and I'm not finding much about it on google. Certainly
               | nothing from scientific or authoritative sources. I guess
               | one article from FT uses the term to describe China's
               | population decline.
        
               | overtomanu wrote:
               | My theory is that, as of now population might be above a
               | "equilibrium". Since it is above equilibrium, it causes
               | increased economic competition to raise kids. So only few
               | economically well off couple have kid's.
               | 
               | After few generations, population comes back to some
               | level where economic competition to raise kids is
               | reduced. Also, most of the lineages of people who chose
               | not to have kids would have been wiped out or atleast
               | somewhat reduced (Natural selection at play). So the
               | people living in the future are likely to have kids on
               | the condition that there is no economic penalty.
               | 
               | So humanity extinction due to demographic decline is less
               | likely. Instead it might happen due to something like
               | nuclear war. More details: https://en.wikipedia.org/wiki/
               | Fermi_paradox#It_is_the_nature...
        
               | vlovich123 wrote:
               | The person making the claim gets to present the data
               | supporting it.
               | 
               | It depends on what you mean by collapse. Is it that
               | population will decline globally for a bit to a new
               | equilibrium point? Sure I can believe that because
               | boomers were a huge population bubble after WWII and
               | there have been lots of living standard advancements
               | since then (a huge one being family planning options
               | being more and more available to the world's population).
               | It's also important to remember that the population
               | bubble was also driven by significant life extension and
               | health advancements in medicine and nutrition without any
               | real birth control being available so the lag until birth
               | control became available results in another population
               | bubble.
               | 
               | None of that is particularly dire. And btw, it's not even
               | clear to me that the population will actually start
               | decreasing. And even if it does, believing it's some
               | runaway effect that can't be fixed within 20 years once
               | we notice it seems myopic as well.
               | 
               | The position you're taking though, that population will
               | not only decline but that there's no bottom to it and
               | society will collapse, is the Elon Musk doomer talking
               | point that this somehow portends the end of countries or
               | civilizations or humanity itself. There's simply no
               | evidence and no realistic mechanism of action for
               | something that extreme. Human populations have always
               | ebbed and flowed and the exponential growth we've seen
               | since the Industrial Revolution is not the norm nor is it
               | sustainable.
               | 
               | > This is not a fringe theory. The effects of the
               | collapse we can theorise on, but the collapse will happen
               | now. It's not a question or a theory
               | 
               | Again - you've stated something quite extreme without
               | providing any support and then tried to shift the
               | responsibility for providing evidence to the person
               | doubting your wild claim. That's not how it works, sorry.
               | It is a hypothesis that there's demographic collapse
               | until it's either happened or there's credible evidence
               | it will happen. Right now afaik neither is true.
        
               | safety1st wrote:
               | I'm downvoting this because of the arrogant and dubious
               | notion that people who've chosen not to have children are
               | somehow morally flawed. The fact of the matter is that
               | successfully raising, educating etc. a child is
               | dramatically more expensive than it was a few generations
               | ago. While we can debate the various reasons for the
               | decline in the reproduction rate there's no doubt that
               | this is a big one, not as many people can _afford_ to
               | raise kids.
               | 
               | The factual and pragmatic view today is that if you can't
               | afford a large home, one parent taking a lot of time off
               | of work, and $120K+ in education bills then you are not
               | setting your offspring up for success, this is not based
               | on your personal morality, it is based on economics, and
               | on statistical observations of the population.
               | 
               | Ergo your lionizing of people who have have children
               | actually amounts to a defense of the economically
               | privileged, and you assert that the benefactors of the
               | systemic increase of wealth inequality in our society are
               | the most moral people. It's despicable really. Go eat
               | your cake, pig.
        
               | eks391 wrote:
               | I don't believe whether ones finances allowing someone to
               | have children is the factor for whether they will. From
               | my observation (i have not researched this; this is
               | anecdotal), wealthier people opt to have fewer or no
               | kids, and larger families are usually those of lower
               | income, like there's an inverse relationship between
               | wealth and desired number of children. Even I used to
               | want a large family until I acquired a higher standard of
               | living and certain luxuries that I would likely have to
               | give up if I got married and had kids.
               | 
               | There's a popular line of thought that motherhood is
               | below a working woman, and men and woman alike are
               | enjoying increased ease of living and a consumerism
               | lifestyle. The folk who still have to stretch and
               | sacrifice to make ends meet already have the mindsets
               | needed for children (sacrifice, hard work) and aren't
               | affected by the line of belief that motherhood is 'below'
               | since they already have learned not to compare themselves
               | to others.
               | 
               | Again this is speculation. I am not a sociologist.
        
               | safety1st wrote:
               | There used to be some truth to that but not so much
               | anymore. It's historically correct that the poor used to
               | have more kids (and I think are still a bit more likely
               | to have them than the middle class). But what started to
               | happen about 10-15 years ago was that _everyone_ became
               | less likely to start a family _except_ for rich people.
               | To be precise if a woman is rich enough to afford
               | childcare she 's much more likely to have kids.
               | 
               | Here's an article on the topic: https://www.theguardian.c
               | om/lifeandstyle/2014/oct/25/women-w... - that's about a
               | decade old and the evidence/trend has only grown.
               | 
               | Children are just another one of those things that is
               | increasingly out of reach for the American middle class,
               | along with property ownership, health care etc. For the
               | poster I responded to to ignore the economic data and
               | paint the middle class and ordinary human beings as being
               | selfish and immoral is perverse.
        
               | Dalewyn wrote:
               | >wealthier people opt to have fewer or no kids, and
               | larger families are usually those of lower income, like
               | there's an inverse relationship between wealth and
               | desired number of children.
               | 
               | I've also noticed this trend, richer societies have less
               | children and poorer societies have more children.
               | 
               | Absolutely no politician (aka the people charged with
               | population and demographic concerns) actually points this
               | out, though. Probably because it goes against a _lot_ of
               | narratives and the simple solution it implies is brutally
               | unpalatable for pretty much everyone.
               | 
               | I also notice that every single would-be or could-be
               | parent inquired says they can't afford it, while also
               | clearly enjoying _many_ luxuries that being poor would
               | actively prohibit. I presume they all keep claiming the
               | issue is money because who doesn 't like free handouts
               | from the government just by saying you'll have kids? Get
               | 'em while the getting's good. I'm not talking about just
               | the US, either.
               | 
               | Anyway, I believe the only true solution to declining
               | birth rates is simply to become poor again as a society.
               | It's the only logical solution when becoming richer
               | clearly leads to less children.
        
               | tanepiper wrote:
               | It's not just economics. I earn a good salary and own my
               | house, but I'm on my second marriage as both my partner
               | and I have ADHD and Autism and in our 40s.
               | 
               | It's not fair to try raise a child in those conditions,
               | so we choose not to for their sake more than ours.
        
             | laeri wrote:
             | They are involved in helping their queen produce new
             | offspring that also contains part of their own genetic
             | material. In bees and ants you have to think of them as one
             | single individual. Each single worker is not able to
             | reproduce but they still will indirectly still reproduce
             | through their queen. Not sure what being good humans has to
             | do with this.
        
             | BurningFrog wrote:
             | Ants and bees in a hive have _very_ similar genetics.
             | Typically 75%, and sometimes 100%, if I remember.
             | 
             | This means that a hive in some ways is best thought of as a
             | single organization, which happens to have a "distributed"
             | body.
             | 
             | In that view, the non reproducing individuals _are_
             | propagating their DNA in the same sense that human liver
             | cells do, even though they don 't have the direct
             | involvement that down and egg cells do.
        
               | derac wrote:
               | Human beings are 99.9% genetically similar to each other.
               | Also, we're about 99% genetically similar to chimpanzees.
        
               | inciampati wrote:
               | In the euchromatic regions, yeah, it's about that.
               | Elsewhere (e.g. centromeres) we are all quite diverse.
               | This is recent news due to long read sequencing and
               | complete genome assembly. The human pangenome project is
               | touching on this, if still reticent to make clear claims
               | about the centromeres.
               | 
               | I'm not sure that "99%" similar is the right way to think
               | about chimpanzees and humans. We have a different
               | chromosome number. Our chromosome 2 is a roberstonian
               | fusion of two acrocentric chromosomes found in all other
               | great apes, including chimpanzees and bonobos.
        
               | lynguist wrote:
               | And 30% to a tomato. So what?
               | 
               | The basics of cellular respiration are always the same on
               | this planet.
        
               | pi-e-sigma wrote:
               | https://en.wikipedia.org/wiki/Sulfate-
               | reducing_microorganism
        
               | BurningFrog wrote:
               | That's a different kind of percentage. The terminology is
               | unfortunate and confusing.
               | 
               | I'm taking about the sense in which you share 50% of the
               | DNA with a sibling or payment.
        
             | jmyeet wrote:
             | This is a perfect example of what I like to call the Eggs-
             | Waffles Phenomenon. Basically, you can't say something like
             | "I like waffles" on the internet without someone replying
             | "how dare you malign people who like eggs". And here
             | there's not even a value judgement or personal preference
             | yet this has somehow been perceived as an attack on the
             | childless. Others have jumped in to bemoan the perceived
             | attack on the family. It's wild.
             | 
             | Nowhere do I argue that you should or shouldn't reproduce
             | or that either outcome affects your perceived or actual
             | value. The word "fail" seems to be doing a lot of heavy
             | lifting in your perceptions here.
        
           | lostlogin wrote:
           | > At some point this number exceeds the number of organisms
           | that were alive at that time so there are likely one or more
           | individuals in the past who are direct ancestors to everybody
           | 
           | Wouldn't this common ancestor be a certainty? Otherwise
           | aren't you betting that there were similar mutations in
           | different lines?
        
           | nostrademons wrote:
           | I suspect a lot of the "woe, things are way harder for
           | Millennials than past generations, I'm too poor to have a
           | family" zeitgeist is actually this phenomena + literal
           | survivorship bias. Every single person alive today came from
           | parents that successfully reproduced. When you're a kid, it's
           | very natural to think that having kids and a family of your
           | own is the default state of being. After all, all of your
           | friends have parents who successfully reproduced too.
           | 
           | But that's because you tend to have much closer relationships
           | with your family and peers than with childless adults. When I
           | change my sample from "my friends growing up" to "my parent's
           | friends when they were growing up", _a lot_ of them never had
           | children. By the numbers, the percentage of households that
           | are families with children has gone down, but it 's gone from
           | about 55% in 1970 to 40% in 2022, which is a much less
           | drastic fall than most people would suspect. Being childless
           | is far more normal than children believe.
        
             | InSteady wrote:
             | You raise an interesting point, but you also seem to be
             | conflating two things. Having children is more expensive
             | than ever, and purchasing power has continued to drop for
             | decades. Not to mention the drastic increase in specific
             | "raising a family" essentials/barriers like housing costs,
             | medical debt, educational debt, and childcare expenses. I
             | don't have numbers to back this up, but my intuition (based
             | on observation and casual reading) is that more working
             | class people who actively want to have children are not
             | doing so because they are stretched too thin than we saw in
             | the 1970's (when people could work part-time to pay for all
             | 4 years of college and expect a high paying career out of
             | their degree).
             | 
             | Also, a 15% drop in 50 years is nothing to scoff at. In
             | America, we are below the replacement fertility rate of 2.1
             | children per woman. Currently it is at 1.7, so our
             | population would be declining without immigration. [1] This
             | is not a bad thing in my opinion, but it is extremely
             | significant in terms of politics, culture, and economics.
             | If our fertility rate continues to drop expect to start
             | hearing about it more often and at higher volume from many
             | different corners.
             | 
             | [1] https://www.cdc.gov/nchs/data/vsrr/vsrr028.pdf
        
             | afavour wrote:
             | Why would any of that be specific to millennials, though?
             | The way you're describing it nothing would have changed in
             | a very long time.
             | 
             | I'm pretty sure the "I'm too poor to have a family"
             | perspective stems directly from the wild increases we've
             | see in the price of housing and not a whole lot else.
        
               | nostrademons wrote:
               | That's the point - nothing has changed, except the
               | narrative.
               | 
               | The wild increases in the price of housing is a symptom
               | of the same dynamic we've seen throughout time, of
               | competition over resources and survival of the "fittest"
               | (where "fittest" occasionally means most
               | brutal/devious/selfish). The differences are that a.) The
               | (white) Baby-boom generation (in the U.S.) bucked the
               | trend and enjoyed abundance and very little selection
               | pressure. Note that the story was very different if you
               | were black (where you had the gains of the Civil Rights
               | movement, only to have the rug pulled out from under you
               | with the 70s inflation and 80s crack epidemic) or if you
               | were Chinese (where you probably died in the Cultural
               | Revolution or Great Famine) or Russian / Eastern European
               | (where you likely drank yourself to death after the
               | breakup of the Warsaw Pact). And b.) that in our
               | "civilized" society, we prefer to let people die rather
               | than kill them outright. Not so for the WW1/WW2
               | generation.
        
           | wruza wrote:
           | _So if you fail to reproduce you will break that billion year
           | old chain of evolutionary success._
           | 
           | True to an extent. What you really break in this case is the
           | last inch change that your parents happened to merge in. Your
           | extended families are still there with almost the same
           | genotype.
        
           | Dalewyn wrote:
           | >So if you fail to reproduce you will break that billion year
           | old chain of evolutionary success.
           | 
           | I sincerely could not care less. As far as I'm concerned, my
           | blood ends with me. I have absolutely no interest in
           | continuing this endless cycle of bullshit.
           | 
           | You are welcome to have babby, of course, and to also do so
           | in my stead if you are exceedingly concerned about the
           | population count that I won't help grow or maintain, I ain't
           | stopping you since what you do in your bedroom is none of my
           | business (and vice versa, if the above wasn't clear enough).
        
           | _0ffh wrote:
           | Here's another, superficially quite perplexing one: Your
           | female ancestors vastly outnumber your male ancestors.
        
             | overtomanu wrote:
             | For those wondering, I think this is mostly because of men
             | having multiple wives.
        
               | JPLeRouzic wrote:
               | I don't understand that, IMO it's more than only high
               | cast/class men could reproduce, others were used as
               | slaves/living tools. Isn't the main change brought by the
               | Neolithic?
        
               | _0ffh wrote:
               | Imagine drawing your ancestry tree, parents,
               | grandparents, etc. you will of course have as many male
               | as female nodes. The higher variance of male reproductive
               | success makes it likelier for two given male nodes to be
               | filled by the same infividual, than for two given female
               | nodes.
               | 
               | Ed. Of course this only works if some males have more
               | than one reproductive partner over their life span.
               | Serial monogamy, escapades, and polygynie are the obvious
               | probable factors in skewing the symmetry. I might have
               | missed some less obvious ones, but can't think of any
               | right now.
        
         | nkrisc wrote:
         | Even the current version fails on its own quite often.
        
         | pfdietz wrote:
         | There's a reason religious types recoiled from Darwin's idea.
         | It paints God as a vivisectionist on the grandest scale.
         | 
         | Darwin experienced this as a father, watching his oldest child
         | die slowly and horribly (probably from cerebral tuberculosis).
         | It would not be a stretch to imagine this experience soured him
         | on traditional religious dogmas.
        
           | lotrjohn wrote:
           | According to Wikipedia it was Darwin's _second_ child (eldest
           | daughter). I believe that is who you are referring to.
           | 
           | https://en.m.wikipedia.org/wiki/Anne_Darwin
        
             | pfdietz wrote:
             | That's who I meant, yes.
        
       | Sakos wrote:
       | This seems to be a common thing. We're an amalgamation of
       | different viruses and bacteria that somehow over billions of
       | years coalesced and evolved together into what we are now. I'm
       | never not astounded when I think about it.
        
       | zakki wrote:
       | If every part of a human coming from evolution, how it
       | synchronize between each part? Is there any books explaining
       | evolution in detail? How cell formed? How they found a way to
       | multiply? How they choose DNA to store the information? And so
       | on.
        
         | getoffmycase wrote:
         | There is literally a world of biology (text)books that describe
         | the process of evolution and how life came to be. I would
         | recommend finding a syllabus at a local college for a biology
         | class, getting the textbook second hand and then reading it
        
         | taneq wrote:
         | It doesn't. Everything that's poorly 'synchronized' just dies
         | out and the more effective organisms keep reproducing. This
         | explains basically everything past the original question of how
         | the original self-replicating chemical reaction started.
        
       | dirtyhippiefree wrote:
       | Think about it.
       | 
       | The species that is now Mitochondria was an entirely different
       | species.
       | 
       | We carry Mitochondrial DNA, while the human side is Nuclear
       | DNA...nucleus of every cell.
       | 
       | Birth as we know it wouldn't have happened without a third
       | species invading our cells. We know it as placenta.
       | 
       | Profound that we fight microbes, but without two (that we know
       | about), our species literally (accurate use) would not exist.
       | 
       | At all.
       | 
       | Just, wow.
        
         | deadbeeves wrote:
         | I mean, everything would seem to indicate that mitochondria
         | were assimilated while our ancestors were still microbes
         | themselves. But that aside, our species is the result of
         | _everything_ that happened prior to its appearance, including
         | for example the Cretaceous-Paleogene extinction event. Arguing
         | that we should not attempt to prevent such events (if we 're
         | able to) because it would evolutionarily benefit the survivors
         | is suicidal.
         | 
         | There's nothing special about our species. If things had
         | happened different would the species that would have been in
         | our place (whatever that means) be better or worse by any
         | metric one chooses? There's no point in wondering about that.
        
           | dirtyhippiefree wrote:
           | Yes, our ancestors were simpler...clearly.
           | 
           | We aren't the only species with the placenta...horses, for
           | example...
           | 
           | One species among many.
        
       | pitdicker wrote:
       | > The syncytiotrophoblast is the outermost layer of the placenta,
       | the part that is pressed against the uterus. It's literally a
       | layer of cells that have fused together, forming a wall. ...
       | There's no other structure like this anywhere else in the body."
       | 
       | > When evolutionary biologists like Chuong mapped the genomes of
       | these cells, they found that the protein that allowed these cells
       | to fuse into a wall, called syncytin, didn't look like it came
       | from human DNA. It looked more like HIV.
       | 
       | So the entire premise of the placenta evolving from a virus rests
       | on the fact that the organ has a unique function requiring a
       | unique protein in the body. Saying the source probably is a virus
       | seems quite a leap of thought. And aren't there many highly
       | specialized proteins in the body?
       | 
       | Has anybody has some more information on what protein in a
       | retrovirus looks similar to syncytin?
        
         | pitdicker wrote:
         | Paper that discusses similarities between the envelope
         | glycoprotein of retroviruses and syncytin:
         | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3758191/
         | 
         | This field is called paleovirology, and the paper also
         | discusses in some more detail how fragments of viral DNA can
         | end up in human DNA.
        
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