[HN Gopher] Scientists generate XX and XY cells from a single pe...
___________________________________________________________________
Scientists generate XX and XY cells from a single person
Author : Amorymeltzer
Score : 150 points
Date : 2022-12-21 13:30 UTC (9 hours ago)
(HTM) web link (www.scientificamerican.com)
(TXT) w3m dump (www.scientificamerican.com)
| colpabar wrote:
| zoklet-enjoyer wrote:
| Nothing
| AxEy wrote:
| Honest question:
|
| Literally every nonbinary person I know (with the exception of
| a tiny number of people who _also_ happen to be intersex) and
| everyone that I know that knows a non-binary person or has done
| the slightest bit of research into the issue, is _well_ aware
| that being non-binary is not a matter of chromosomes but rather
| a matter of gender roles.
|
| Were you genuinely unaware of this, or did you have some
| different goal in asking this question?
|
| I feel like I may be downvoted, but it's hard for me not to
| read your question as trolling (and if so it's working; see
| sibling responses). If I am wrong I apologize.
| sverona wrote:
| Nonbinary genders have as much do to with karyotypes as a grape
| has to do with grapefruit.
|
| Alternatively, go read that short story by Isabel Fall.
| drowsspa wrote:
| Why would it have anything to do with it? Being trans is about
| the brain development, not about the chromosomes.
| verdenti wrote:
| at_a_remove wrote:
| Same as veterinary advances mean for furries: it has nothing to
| do with their imaginary identity.
| russdill wrote:
| Just because gender is a societal construct doesn't mean it's
| imaginary.
| sverona wrote:
| at_a_remove wrote:
| Fortunately for me, I don't care if you think it is real or
| not. I'm also not suggesting that it is a "hate crime" for
| you not to play along. By all means, descend into
| solipsism!
| sverona wrote:
| What I think doesn't matter. Personal identity is
| constructed _by definition._ Your identity is no more or
| less real than mine. That 's all.
| at_a_remove wrote:
| "What I think doesn't matter." Agreed.
|
| "Personal identity is constructed by definition." --
| tentative agreement on the _personal_.
|
| Ah, but that last one. No. Your identity is no more or
| less real than mine ... _TO YOU_. If you decide that your
| personal identity is that of a six year old girl named
| "Stefonknee," that may be real to you (you might claim in
| insincerely), but it certainly isn't real to me.
|
| That's all.
| sverona wrote:
| You can perceive what you will. Your identity is no more
| or less _objectively real_ than mine.
| at_a_remove wrote:
| I can agree with that statement. It just doesn't jibe
| with the bit you ignored above: forcing another person to
| play along with the fantasy of someone else's identity,
| trying to make "misgendering" a crime (which itself can
| be rather incoherent, you cannot misgender someone who
| claims that gender doesn't apply to them).
|
| It's the being forced to play along with the six-year old
| Stefonknee's playtime to which I object. Evading it with
| solipsism and "what your definition of 'is' is" word
| games is a distraction.
| sverona wrote:
| You bristle at "being forced to play along with a
| fantasy" because you prefer a different and equally
| fantastic fantasy.
|
| And who's forcing you into anything? Who's trying to make
| misgendering a crime? It's _impolite,_ the same as
| violating any other boundary is --- imagine if I started
| doing it to you on purpose --- but there is no possible
| way for it to be legally codified in an enforceable
| manner, and I can assure you that trans people _don 't
| want that anyway_.
| politician wrote:
| Doesn't this line of reasoning lead you to necessarily
| conclude that the other's identity is strictly less
| objectively real than your own? Your identity is
| continuously simulated on your own wetware, but the
| other's identity simulation has only recently started
| running and suffers from a low synchronization rate.
|
| TLDR: For all you know, your sparring partner is ChatGPT.
| sverona wrote:
| This gets into some philosophy-of-mind weeds that I may
| not be well equipped to navigate, but my contention is
| that identities aren't objectively real at all. They are
| constructions. They're as _real_ as the real line.
| dang wrote:
| Please stop posting flamewar comments. We ban accounts that
| do this, and your comments in this thread have been
| particularly flamey.
|
| If you'd please review
| https://news.ycombinator.com/newsguidelines.html and stick to
| the rules when posting here, we'd appreciate it. Note this
| one:
|
| " _Comments should get more thoughtful and substantive, not
| less, as a topic gets more divisive._ "
| birdsink wrote:
| It's very difficult to go through life being treated with
| disdain, which is the treatment a lot of nonbinary and
| transgender people get. Even if you think it's justified, you
| don't have to be the reason their lives are difficult.
| blueflow wrote:
| Is the emotional well-being of people more important than
| admitting to uncomfortable truths?
|
| Should i be able to force you to pretend im not balding?
| commandlinefan wrote:
| > force you to pretend im not balding
|
| Huh, that's an interesting analogy and not one I'd ever
| really thought about before. After all, there _are_
| people with terrible combovers and toupees that most
| people pretend they don 't notice (no offense if that's
| you, OP). I'm trying to imagine how much "not playing
| along" you'd have to do before you ended up in HR over
| it, and I'd think it would have to be quite a bit -
| certainly just pretending you didn't notice and not
| agreeing or disagreeing when the guy in question says his
| hair is completely natural wouldn't be enough.
| jl6 wrote:
| The hair analogy would be a person feeling distress at
| having hair, and so shaving it off. They shouldn't be
| harassed for doing this, but they would cross a line if
| they then sought a place in an alopecia support group.
| homonculus1 wrote:
| dang wrote:
| We've banned this account. Please don't create accounts
| to break HN's rules with.
|
| https://news.ycombinator.com/newsguidelines.html
| at_a_remove wrote:
| Gabriel_Martin wrote:
| Based on those questionably real experiences relating to
| your coworker's pronouns and last name, it kinda seems
| like you decided in advance to now plant your flag on
| being standoffish and pretty foul towards people who
| chose not to act as sex they were assigned at birth, by
| calling their gender identity "imaginary" when the topic
| comes up. Which is just prejudice I think? Kind of a pick
| your battles moment really, are you really going to
| preemptively be irritated at any mention of nonbinary or
| trans people forever?
| at_a_remove wrote:
| At the mention? No. At the _having to play along_.
| Gabriel_Martin wrote:
| Well, this is all based on my perception and feeling, but
| in this case at least it appeared to be merely at the
| mention of how this story might relate to nonbinary
| gender identity. Just my perspective, but you appeared to
| really jumped at the opportunity to describe their their
| gender identity as imaginary and liken it to a sexual
| kink (are kinks imaginary either? IDK). Just seems as if
| this topic has fallen into the focus of your ire, which I
| just feel is a bit prejudiced.
|
| For you it's at worst an extremely rare, uncomfortable
| but minor inconvenience to you. But now you jump at this
| kinda shitty reactivity towards the topic, which must
| sorta stink for other HN readers who just try to live
| their lives, but happen have a nonbinary or trans gender
| identity. IMO you're just piling on in a needlessly
| irritable way.
|
| Just an outsiders perspective. Happy holidays and I hope
| you have a nice rest of your day, fwiw.
| tosc wrote:
| Agreed, however the waters have been muddied by trans-
| activists attacking and threatening people for simply
| saying things like 'women are not men', or claiming that
| biological sex is more than a social construct.
|
| Activists are legitimizing the idea that non-binary people
| are irrational, and thus now provoking disdain.
| ppopp wrote:
| Perhaps it is legitimate to hold that view. I mean, the
| concept of non-binary requires holding the irrational,
| non-empirical belief that men and women are loosely
| defined as a set of sexist stereotypes, rather than sex.
|
| They've taken a socially conservative ideal of what women
| and men should be like (per whatever culture they're in),
| assumed that this is what actually defines women and men,
| and decided to carve themselves an opt-out in the form of
| an extra category. When they probably should be taking a
| step back and wondering why they hold these rigid
| definitions of men and women in the first place, and
| applying some critical thinking.
| tosc wrote:
| > I mean, the concept of non-binary requires holding the
| irrational, non-empirical belief that men and women are
| loosely defined as a set of sexist stereotypes
|
| I don't think there is anything irrational about the view
| that gender expression is in part based on stereotypes
| and social construction. Cross cultural and
| intergenerational comparisons clearly show that there are
| cultural differences in how genders are expressed.
|
| It is not irrational to believe that some people are
| drawn to gender expressions not traditionally associated
| with their biological sex, nor is it irrational to
| suppose that there is suffering associated with being
| prevented from doing so, or humiliated or ostracized if
| they do.
|
| What is irrational is to claim that there is no such
| thing as biological sex, that sex rather than gender is a
| continuum, and that the only difference between a man and
| a woman is what someone claims themselves to be.
| talideon wrote:
| Except that's not what they claim, at least not in the
| way you're claiming, which seems deny that there are men
| and women out there with sex genes other XY and XX and
| that intersex people don't exist. Because when people
| claim that "sex is a continuum" it's pointing out that
| while men and women cluster around having XY and XX
| chromosomes, the reality is more complicated.
|
| People can be intersex, people can have sex gene
| aneuploidies, people can have male sex genes buy end up
| developing as females, as can the reverse happen. Such
| people are a minority, but they do exist, and that's what
| the spectrum is. And in case you're thinking the numbers
| are vanishingly small, they're not: intersex people alone
| are more common than red heads.
| ppopp wrote:
| Those are discrete, sex-related developmental conditions,
| e.g. males with Klinefelter syndrome, females with
| trisomy X, etc.
|
| People with these conditions aren't middling points on
| some sort of male-female 'sex spectrum', as there's no
| continuous variable of sex from which one could obtain a
| value.
|
| This idea that sex is a spectrum really is nonsensical.
| Gabriel_Martin wrote:
| Isn't sex a bimodal distribution, and therefor
| objectively a spectrum?
| ppopp wrote:
| A bimodal distribution of what?
| Gabriel_Martin wrote:
| Of sex characteristics, I mean if I was attempting to be
| accurate as possible to what sex is, it'd be some
| composite of morphology, chromosomes and gamete
| structures, which would place most humans in two main
| tranches, but some individuals would fall in between or
| outside of those two, which sounds a lot like a spectrum
| to me.
| ppopp wrote:
| A composite how exactly? What are you measuring, how are
| you translating it to a continuous variable, and why are
| you calling this variable "sex"?
| Gabriel_Martin wrote:
| Not that we're debating, but your reply seems a little
| gish-gallopy. What type of information are you seeking by
| asking "A composite how exactly"?
|
| Are you asking how what I described is a composite? How
| I'd create a composite? If I were trying to define sex,
| I'd try to find the most relevant attributes to human
| sexual dimorphism, and if and when I encountered
| exceptions, to me that would imply a spectrum exists and
| sex is non-binary.
|
| What am I measuring? I'd be trying to find the biological
| measures relating to sexual dimorphism, and how they
| consistently they correlated to the other biological
| measures I listed. I'd also be looking for exceptions,
| which do certainly exist.
|
| How are you translating it into a continuous variable? I
| wouldn't be, I imagine that upon seeing that there are
| exceptions to the attributes I included in my composite,
| where people in one or more ways fall outside of the two
| typical morphological/gamete/chromosomal norms, that
| would be what implies a continuum/spectrum. I'm not
| translating it, I'd just be seeing nonbinary data, I
| didn't translate the data to fall outside of a binary
| pattern or force it into a continuum, it just exists that
| way. Correct me if you think I'm wrong.
|
| Why are you calling this variable sex? As I said, in my
| best attempt to create a composite of all traits that
| could be contained within a definition of sex, that's
| what it'd be.
| tosc wrote:
| > Except that's not what they claim,
|
| Yes it is.
|
| > at least not in the way you're claiming,
|
| In exactly the way I'm claiming.
|
| > which seems deny that there are men and women out there
| with sex genes other XY and XX and that intersex people
| don't exist.
|
| You are reading something in that I didn't write. I
| didn't deny the existence of intersex people or those
| with chromosomes other than XX and XY.
|
| > Because when people claim that "sex is a continuum"
| it's pointing out that while men and women cluster around
| having XY and XX chromosomes, the reality is more
| complicated.
|
| It's true that reality is more complicated than XY and
| XX. But then I never said it wasn't.
|
| It's not true that people are "just pointing this out".
| They are deploying this read herring as as the Motte part
| of a motte and Bailey argument.
|
| It's true that there are certain discrete exceptions to a
| rigid sex binary. This is the easily defensible 'motte'.
|
| It's plainly not true that there is no such thing as
| biological sex. You might like to learn about the
| processes surrounding your conception and birth if you
| are unsure.
|
| It's also false that declaring that you identify as a
| different gender does anything to change your biological
| sex, regardless of your chromosomes.
|
| These are the absurd 'Bailey' arguments that the red
| herring is disingenuously used to defend.
|
| https://en.wikipedia.org/wiki/Motte-and-bailey_fallacy
|
| https://en.wikipedia.org/wiki/Human_reproduction
| kingkawn wrote:
| It ain't the activists fault society has been so vile to
| those populations that they had to turn to extreme public
| instigations to get any attention and subsequent respect
| at_a_remove wrote:
| "They made me do it!" -- every abuser ever.
| kingkawn wrote:
| incoherent comparison, as expected
| at_a_remove wrote:
| sverona wrote:
| One joke.
| throwawayacc3 wrote:
| Do you show your partner's boyfriend this every time you
| post "one joke"? Ah shit that's two jokes now...
| at_a_remove wrote:
| sverona wrote:
| There are at least three basic formats that the One Joke
| comes in:
|
| 1. "I identify as X." Okay, how should I address you?
|
| 2. "X (nonsentient) identifies as Y." Nonsentient objects
| don't have identities.
|
| 3. "X (sentient) identifies as Y." This may or may not be
| a statement of fact, but if you're using someone else's
| identity as a punchline, what's that say about you?
|
| Your prior comment falls under case 2.
| tosc wrote:
| > It ain't the activists fault society has been so vile
| to those populations
|
| This is true.
|
| > that they had to turn to extreme public instigations
|
| This is false. Activists don't have to turn to an
| obviously incoherent ideology, nor do they need to harm
| people who are not harming them.
|
| > to get any attention and subsequent respect
|
| They have attention, but they haven't gained respect. In
| fact they have reduced it. Activists don't represent
| anyone but themselves, and through their actions are
| harming the very communities that claim to support.
| koollman wrote:
| stevenwoo wrote:
| To spoil an old book, this happens in The Time Traveler's Wife,
| and the character does have that thought.
| [deleted]
| aatd86 wrote:
| Yourself? It's more like your twin sister or brother at this
| point. I don't think you'd do that do you? :}
| Woshiwuja wrote:
| DrThunder wrote:
| walnutclosefarm wrote:
| What was accomplished here occurs in nature, in a condition
| called sex-hormone discordant chimerism, where replication errors
| in embryos result in persons who have a mix of otherwise
| identical (in terms of genetics) male and female cells in their
| body. In very rare cases this can result in intersex morphology
| (https://www.nature.com/articles/s10038-020-0748-4). Generally in
| mammals, though, such chimerism doesn't result in dramatic
| phenotypic variance from normal male/female morphology. This is
| because mammalian secondary sex characteristics expressed by
| cells are mostly determined by the hormone bath the cells live
| in, so if a body has wholly or overwhelmingly one-sex gonads,
| they will develop as that sex. The situation is quite different
| in insects in birds, where secondary sex characteristics are
| largely determined by the sex chromosomes of individual cells.
| This leads to some dramatic phenotypes, such the bilateral
| gynandromorph (e.g.,
| https://www.birdnote.org/listen/shows/cardinal-thats-half-ma...).
| pavlov wrote:
| ed25519FUUU wrote:
| I find that children understand the concept thoroughly and
| without much effort or mental gymnastics. Adults on the other
| hand, quite the opposite.
| shrimp_emoji wrote:
| Sex is not the same thing as gender.
| funstuff007 wrote:
| other than edge cases, though...
| mbg721 wrote:
| Alternatively, we can't think sexual practice is in any way a
| willful choice, or else we're demanding a backward theocracy.
| fallingfrog wrote:
| I don't understand your comment. Having a gender is not a
| sexual practice.
| mbg721 wrote:
| Having a sex at birth isn't, but the idea of gender being
| a separate thing from gender is contentious precisely
| because it's connected to sexual practice.
| fallingfrog wrote:
| Allow me to play Socrates here. How is it connected to
| sexual practice? In what way?
| mbg721 wrote:
| Because there's no particular reason to act differently
| from your birth sex other than for sexual practice. What
| else does gender actually mean, if it means anything at
| all? The fundamental conflict of the current culture-war
| is "Is sexual attraction a choice or is it innate?" and
| "It's innate" is the only polite thing to say, but it
| also creates contradictions.
| fallingfrog wrote:
| "there's no particular reason to act differently from
| your birth sex other than for sexual practice"
|
| When a four year old wears a dress and plays with dolls,
| are they doing it for a sexual practice? I don't think
| so.
|
| Your response seems to imply that if a cis woman puts on
| a dress and walks down the street to buy a cup of coffee,
| then it is not sexual, but if a transwoman does exactly
| the same thing in exactly the same way, then it becomes
| sexual. Why?
|
| Let me pose a possible explanation: Perhaps the
| difference between these two scenarios is in _your_ mind,
| not the cis or trans woman 's. In which case, the trans
| woman cannot really do anything about the sexual thoughts
| in _your_ head, can she?
|
| "What else does gender actually mean, if it means
| anything at all?"
|
| This is just restating the question I asked. But: I have
| a gender, and it's my gender when I'm eating lunch, and
| when I'm brushing my teeth, and at all times in between,
| and those are not sexual practices. I put on clothes in
| the morning, and they are gendered clothes, but they are
| not revealing or sexual, nor is wearing clothes a sexual
| practice. So how is it different for a trans person? The
| greatest aspiration of most, if not all, trans people is
| to "pass", meaning that they become invisible and nobody
| know they are trans. In what way is that sexual?
| mbg721 wrote:
| fallingfrog wrote:
| "sexually-maladjusted adults who are using the ability to
| hide behind an identity as a way to fulfill their kinks"
|
| This is no less of an offensive stereotype than saying
| Mexicans are lazy, or something like that. I had a
| feeling that your reasoning would come down to something
| like that, and sure enough..
| mbg721 wrote:
| Maybe in 50 years I'll sound as cringey as Song of the
| South or something, but I still maintain that gender
| identity is a created social phenomenon and that
| encouraging alternative identities is destructive.
| mcguire wrote:
| What other "created social phenomena" do you think are
| destructive to "encourage alternatives"?
| maria2 wrote:
| What part of the law does this violate, explicitly?
| pavlov wrote:
| It's a joke. I thought the "under 21" part would give it
| away, but I guess not.
|
| Satire is a difficult art, but I'll suffer the downvotes
| with dignity and the slightest tremble of the lip.
| gpvos wrote:
| With what I'm hearing about US politics, it sounded
| perfectly plausible to me.
| [deleted]
| luxuryballs wrote:
| jcampbell1 wrote:
| Let's not blame pharmaceutical companies here. I have done
| some research and looked for any pharmaceutical companies
| involved and can't find any (for purposes of short-
| selling). The medical side is advanced through doctors and
| hospitals using off-label generics and profitable
| procedures and surgeries. Pharmaceutical companies have out
| right rejected spending a dime on research in this area as
| they all know it is a land mine. On the one hand we have
| various doctors organizations saying it is "established
| science" and all the pharma companies regard it as highly
| experimental and do everything to distance themselves.
| fallingfrog wrote:
| FYI I'm pretty sure you meant to link a different nature
| article, the one you linked is something about methane
| emissions from wetlands.
| walnutclosefarm wrote:
| Thanks for catching that. Fixed.
| michaelsbradley wrote:
| parent seems to have fixed it: by following the link, I got
| an article titled _A Cardinal That 's Half Male, Half
| Female_.
| kibwen wrote:
| The other difference with birds is that males are the
| homogametic sex, with ZZ chromosomes, whereas females are the
| heterogametic sex, with ZW:
| https://en.wikipedia.org/wiki/ZW_sex-determination_system
| matrix12 wrote:
| But they are trigametic and not bigametic.
| version_five wrote:
| The title used to say Male and Female (not XX/XY), and that's the
| title of the actual article. Normal HN policy is to keep the
| article title unless it's long or clickbait. Why was it edited?
| dang wrote:
| Because it was clickbait and arguably misleading as well.
|
| Note that we replaced it with what the article itself says it's
| about, once it gets to the stage of actually saying that.
| cjtrowbridge wrote:
| The article title is a factually incorrect representation of
| the study being discussed. If you read the article and the
| study, you'll see the study was about changing chromosomes in a
| cell line, not about changing the sex of a person.
|
| Everything about primary and secondary sex characteristics
| would not be affected by changing someone's chromosomes.
| Homologous sex structures diverge before birth based primarily
| on dht metabolism. Even then, chromosome expression doesn't
| always determine how dht will metabolize, meaning whatever
| chromosomes a person has can still lead to someone having any
| kind of primary and secondary sex characteristics. The six most
| common sex chromosome patterns in humans are XX, XY, XXY, XYY,
| X, and XXXY (in that order).
|
| Sex and gender are both far more complex than merely chromosome
| expression, and chromosome expression is anything but a binary.
| This study has nothing to do with being male or female.
| Aarostotle wrote:
| From the article:
|
| > "This is a very well-designed study that validates the
| notion that sex differences start early in development--and
| that they depend on the sex chromosomes because that's the
| only thing that can account for those differences," says Nora
| Engel, a professor of cancer and cell biology at Temple
| University, who was not involved in this work.
|
| Is this your area of expertise?
| [deleted]
| gizmo686 wrote:
| I can't speak for whoever changed the title, but XX/XY is far
| more accurate and less clickbaity than Male/Female in this
| context.
|
| There is far more to human biological sex than the chromosomal
| distinction. Take an XY cell, but it in an otherwise female
| body, and it will, in many ways, express itself similar to that
| of an XX cell. This is the theory behind hormome replacement
| therapy (HRT).
|
| That is not to say that an XY cell in a female body would be
| identical to an XX cell in the same. For instance, an XY eye in
| a female body would likely be similar to a male eye with
| regards to color blindness; because we have traced
| colorblindness directly to a chromosonal difference.
|
| However, most sex differences (in humans) are not chromosonal.
| Instead they are triggered by a single gene (SRY), that just so
| happens to occur on the Y chromosone. That single gene codes
| for a protein that triggers almost all of the sex
| differentiation. Splice that single gene onto a X chromosome
| and you can get an XX human that appears male.
|
| Exactly what differences are directly chromosomal, and what are
| developmental is a largly open area of research, and exactly
| what this achievement hopes to further enable.
| anon291 wrote:
| SRY triggers development of testis, but in fact, if you have
| a translocation of just SRY onto X, and thus are an XX male,
| you may have issues with reproduction, as the Y chromosome
| contains other supporting genes for the production of sperm.
|
| We can go on about male v female as a social construct, but
| biologically, males produce the smaller gamete, so if one has
| SRY and has an otherwise male phenotype, but isn't producing
| sperm, from a strictly biological perspective, it's not at
| all clear that the statement 'SRY is the determinant of
| maleness' is necessarily true.
|
| It certainly will make you develop testicles and male
| secondary sex characteristics.
|
| You are correct on the cell naming. Cells cannot be male or
| female. That is a characteristic of a complete person. They
| can be derived from a male or female, but what the scientists
| did here did not change that attribute of a cell.
| kelseyfrog wrote:
| Just curious, what are the potential effects of
| CRISPR/Cas9-mediated knock-out of SRY in adult humans?
| verdenti wrote:
| 752963e64 wrote:
| einpoklum wrote:
| > To create such a model, ... [they] ... obtained ... cells
| previously collected from a person with ... an extra X chromosome
|
| So, the title is rather misleading. They just had to get cells to
| shed one of the three chromosomes, they didn't get an XX female
| to somehow produce a Y, nor an XY male to duplicate their X.
| dang wrote:
| Hmm. If anyone can suggest a better title (i.e. more accurate
| and neutral, preferably using representative language from the
| article), we can change it again.
| automatoney wrote:
| From the article they specify "with Klinefelter syndrome"
| which is the XXY version of trisomy 23. This fits the word
| limit: "Scientists generate XX and XY cells from a person
| with Klinefelter syndrome"
| 323 wrote:
| In a way, all cells are female, because DNA from sperm and egg is
| the software, but it always runs on female hardware (the egg).
|
| This is also why "cloning dinosaurs" might be extremely difficult
| even if you found complete DNA, you lack compatible enough
| hardware to run that DNA on.
| teaearlgraycold wrote:
| Would the DNA not describe the cell it belongs in?
| 323 wrote:
| Not completely. For example mitochondrial DNA is totally
| separate from regular DNA, and it's passed exclusively mother
| to offspring.
|
| It's the old bootstrapping problem - how do you get a running
| C compiler from code if you don't already have a running C
| compiler?
|
| There is no example in nature where you get a fully
| functional cell starting exclusively from DNA.
| njarboe wrote:
| "it's passed exclusively mother to offspring"
|
| As in most absolute statements, this may not be completely
| true. Sperm has some mitochondria that likely is
| incorporated into the zygote.[1]
|
| [1]
| https://en.wikipedia.org/wiki/Paternal_mtDNA_transmission
| tibbydudeza wrote:
| Afaik the mitochondria of the sperm cell is located in
| the tail to power it which then gets detached from the
| head just after it has borrowed into the egg ???.
| LesserEvil665 wrote:
| I am eagerly anticipating the birth of Henry Lacks.
| elektrontamer wrote:
| Haha, pretty good one! Incredible that her cells are still used
| all over the world long after her death.
| kingkawn wrote:
| The 70-90 chromosomes of the HeLa line may not agree to this
| easily
| StevePerkins wrote:
| Is this basically the approach speculated by Neal Stephenson in
| _Seveneves_?
| Ygg2 wrote:
| Not really, they didn't all have Klinefelter's syndrome.
| photochemsyn wrote:
| One takeaway is that the genome is highly integrated, i.e. just
| because there are two sex-linked chromosomes doesn't mean that
| they aren't also interacting constantly with the other 22 pairs
| of chromosomes found in every reproducing human cell (and the
| proteome, and the microbiome, for that matter). From linked
| paper:
|
| > "Although some of the sex differences arise from hormonal
| effects (Gurvich et al., 2018), it is now acknowledged that many
| differences are due to sex chromosome complement (Arnold, 2012).
| Studying the effects of sex chromosome complement on gene
| expression and biological phenotypes is impeded by variation in
| genetic background. Therefore a large sample size is needed to
| identify sex-related differences (Ronen and Benvenisty, 2014). To
| date, there is no human model to study sex differences that can
| overcome the variation in genetic background."
|
| Another complicating factor must be the random nature of
| X-chromosome inactivation in XX cells, as only one of the two
| copies is actively transcribed. Hence even if you clone an XX-
| type cell, its progeny cells will at some point randomly (and
| permanently) switch off one of those X chromosomes (to avoid
| making too many gene products).
|
| > "The two X chromosomes have an equal probability of being
| silenced. Silencing, once established, is stable: the same X
| chromosome remains inactivated in all subsequent cell
| generations. As a result, each female is a mosaic of cells in
| which either the maternally inherited or the paternally inherited
| X is silenced."
|
| https://jbiol.biomedcentral.com/articles/10.1186/jbiol95
| anon291 wrote:
| The other factor unaddressed here is methylation. To form a
| complete human person, as far as we know, you must have one set
| of chromosomes from a female imprinted via an ovum and another
| from a male imprinted via a sperm. If this doesn't take place,
| you may have strange genetic symptoms. Male bodies deactivate
| certain genes and reactivate some others so that, when combined
| with the way in which female bodies do the same thing, the
| resultant genome has a full set of proteins sufficient to form
| of a homestatically stable human.
|
| When this goes wrong, genetic disease can occur such as what
| happens with Angel man and Prader willi syndrome, which is
| caused by the exact same mutation but dependent on the sex of
| the parent it was inherited from.
| hinkley wrote:
| So with X inactivation it sounds like it hardly matters whether
| the X Chromosome is a duplicate or different, other than any
| effects that might be seen by having 100% of your cells be
| behaving a certain way instead of a mix of the two evening some
| things out. Like metabolism, endocrine and renal function.
| shagie wrote:
| > > Silencing, once established, is stable: the same X
| chromosome remains inactivated in all subsequent cell
| generations. As a result, each female is a mosaic of cells in
| which either the maternally inherited or the paternally
| inherited X is silenced.
|
| For those curious about it, a visual example of this is
| tortoiseshell and calico cats.
|
| The orange or black in a cat is X linked. A simple, not quite
| correct, representation of this would be that a male cat can be
| either XoY or XbY while a female cat can be XoXo, XoXb, XbXb.
| The XoXb cats are both black and orange and are frozen at the
| time when one of the chromosomes were silenced.
|
| This is known as X-inactivation and the Wikipedia page (
| https://en.wikipedia.org/wiki/X-inactivation ) even has a
| picture of a tortoiseshell cat.
| [deleted]
| skadamou wrote:
| Interesting. It sounds like they used cells from someone with
| Klinefelter's syndrome (XXY sex chromosomes) but I'm curious if a
| similar technique could be used to generate male and female cells
| from any male (XY sex chromosomes). Does anyone on here have an
| idea of why they needed to start with cells derived from someone
| with "mosaic" Klinefelter's?
| jcampbell1 wrote:
| This individual had T-cells that were: XX, XXY, and XY (mosaic
| Klinefelters), but otherwise genetically identical. They
| collected the XX and XY cells and coaxed them into being stem
| cells. Now researchers can use this stem cell line for
| research.
| skadamou wrote:
| I see. So it was more about capturing the cells with the
| desired chromosomes and converting them to stem cells than
| about creating cells with the desired chromosomes. Thank you
| for your explanation!
| hammock wrote:
| Not a geneticist, but X is not female and Y is not male.
| Rather, XX is female and XY is male. To make XX from a single
| XY person would be to clone the X and I would guess would lead
| to unviability problems when the chromosomes are put to use
|
| Edit: for those downvoting, can you tell me how I'm wrong, if
| that is the case?
| _Algernon_ wrote:
| You're correcting a claim which wasn't made by the GP (Not
| sure if it has been edited though), as well as calling out
| that you're being downvoted which is against HN guidelines.
|
| >Please don't comment about the voting on comments. It never
| does any good, and it makes boring reading.
| withinboredom wrote:
| I'm pretty sure you're the one commenting about voting.
| Their edit asks why they're wrong and using the fact they
| are being downvoted to encourage people to reply.
|
| The replies since then have been interesting and not boring
| at all. Until I got to yours.
| _Algernon_ wrote:
| Fair enough
| bioemerl wrote:
| I think it's because the person you're responding to didn't
| seem to be implying that a single X or a single y would
| count?
|
| Instead, they're probably talking about taking three cells
| with XY, and then using that to create an xx, an xy, and then
| some leftover parts.
|
| If that is the case, your correction might seem arrogant or
| assuming.
| whimsicalism wrote:
| Seems obvious to me why they led with that clarification
| and then directly responded to the point of why you might
| be able to make XX from XXY but not XY.
| nonameiguess wrote:
| Also not a geneticist, but I'm pretty sure this is wrong
| because you only get recombination between analogous autosome
| pairs. The allosomes, or sex chromosomes, you just get from
| one parent anyway. Females get the X from the mother and the
| X from the father, but rather than recombination producing an
| X that is different from either parent, one of them just gets
| deactivated randomly in every cell during embryonic
| development and the offspring ends up with a single active X
| in each cell, usually roughly 50/50 split between exactly the
| same as the father and exactly the same as the mother. This
| is true in placental mammals, but in marsupials, it is always
| the father's X that gets deactivated.
|
| So it seems like making XX from a single XY person would just
| end up doing something genetically similar to what already
| happens with marsupials, which doesn't result in non-
| viability.
|
| Of course, cloning at all does result in not getting genetic
| diversity you would normally get from recombination, which
| can eventually result in population-level problems if you're
| doing enough of it.
| adrian_b wrote:
| The recombination happens when the gametes are produced,
| during meiosis.
|
| While in males there is no recombination between the X and
| Y chromosomes, in females sometimes there is recombination
| between the two X chromosomes.
|
| Therefore the X chromosome received by a child from the
| mother may either be 1 of the 2 X chromosomes of the
| mother, chosen randomly, or it may be a combination of
| those 2 X chromosomes.
|
| The inactivation of an X chromosome happens only in the
| female somatic cells, where the remaining active X
| chromosome is either the X chromosome of the father or 1 of
| the 2 X chromosomes of the mother or a combination of the 2
| X chromosomes of the mother.
| bewaretheirs wrote:
| My understanding is that the master switch for sex
| determination has been identified as the "SRY" gene normally
| found on the Y chromosome. Active SRY means development heads
| down the "male" path in the genes; no SRY (or non-functional
| SRY) means development heads down the "female" path.
|
| SRY can cross over to the X chromosome (resulting in an XX
| male), but the end result is usually sterile as there are
| other genes elsewhere on the Y chromosome that are also
| necessary for complete development.
| WalterBright wrote:
| I suspect that making an XX from the same X would result in
| expression of all the recessive genes, which would be the
| ultimate in inbreeding. Probably with quickly fatal
| consequences.
| [deleted]
| shagie wrote:
| Consider that in all males, all of the X chromosome genes
| are expressed.
|
| What's more, with X inactivation, one of the chromosomes in
| XX becomes almost completely inactive and all of the genes
| on the other chromosome are expressed.
|
| https://en.wikipedia.org/wiki/X-inactivation
|
| > X-inactivation (also called Lyonization, after English
| geneticist Mary Lyon) is a process by which one of the
| copies of the X chromosome is inactivated in therian female
| mammals. The inactive X chromosome is silenced by being
| packaged into a transcriptionally inactive structure called
| heterochromatin. As nearly all female mammals have two X
| chromosomes, X-inactivation prevents them from having twice
| as many X chromosome gene products as males, who only
| possess a single copy of the X chromosome (see dosage
| compensation).
| [deleted]
| anon291 wrote:
| Doubtful. Males methylate their X chromosomes differently from
| females during the production of gametes.
| davidguetta wrote:
| Dumb question but how is this different from a women giving birth
| to either male or female babies ?
| skadamou wrote:
| I don't know if this totally answers your question but sex is
| actually determined by the male haploid cells (sperm). Females
| have XX chromosomes and thus can only produce daughter haploid
| cells with X chromosomes. Males have XY chromosomes and produce
| daughter haploids cells with either X or Y chromosomes. The sex
| of the fertilized zygote is determined by whether an X or a Y
| chromosome containing sperm reaches the egg.
| quickthrower2 wrote:
| I was thinking the same sort of things but my understanding was
| the sperm that carries the determination of sex not the egg.
| hammock wrote:
| Women require a man to contribute before they can give birth
| vjerancrnjak wrote:
| You can convert female cells to sperm cells (using stem
| cells), so male is not required. Although, I believe the
| offspring can only be female.
| gillci wrote:
| WalterBright wrote:
| Species where the male is only of value for impregnation
| tend to have the males die off after impregnation. The
| fact that human males live long afterwards means that
| evolution selected for that to happen because males have
| a critical role in the education, support and defense of
| the children.
| peanutcrisis wrote:
| Why do you need to paint all males with the same brush?
| If what you've described is "applied feminism", I'd
| strongly suggest you take a hard look at your own sexism
| (and genocidal tendencies). I've no horse in this race,
| but such rhetoric is toxic and unwelcome on hacker news.
| gillci wrote:
| Perhaps think of this as a science fiction thought
| experiment instead. It could be an interesting societal
| outcome of such technology, right?
| manquer wrote:
| You could also develop tech to elimate the woman from the
| process and that maybe easier . Genetically speaking in
| broad terms the male geneome contains both XY chromesomes
| and female contains XX and miss the Y.
|
| Practically it is lot more complex with imprinting and
| other interactions.
|
| As a social thought experiment :when such tech becomes
| achievable, it will be likely available for either sex
| and combined with gene editing sex will become more fluid
| and meaningless biologically and only have asthetic
| purpose .
| peanutcrisis wrote:
| I have no issue with thought experiments. However, your
| choice of words (i.e. "useless male") clearly illuminates
| your nasty intent. As such, I can't afford your original
| post any interpretation more charitable than sexism,
| regardless of your attempt to frame it now as a "thought
| experiment".
|
| Edit: In response to your follow up, "useless" can be
| used as matter of fact, or as an implication of
| "worthlessness". Again, your choice of words "applied
| feminism" betrays your claim.
| gillci wrote:
| Well if they're not needed any more to supply sperms,
| then in terms of reproduction they would be useless
| wouldn't they.
|
| That's the only purpose of a male when compared to the
| female - this is a simple fact, no need to take it
| personally.
| nomel wrote:
| Artificial wombs are nearly feasible. I think, in some
| horrible future, your genocidal thoughts could be applied
| to either group.
| BlargMcLarg wrote:
| >That's the only purpose of a male when compared to the
| female - this is a simple fact, no need to take it
| personally.
|
| There is nothing factual about this unless your world
| view is an infantile one which believes the only valuable
| difference between men and women is the ability to create
| sperm vs the ability to carry eggs. Common complaints
| _from women_ clearly reveal that isn 't the case.
| psychphysic wrote:
| It doesn't quite work due to genetic imprinting.[0]
| basically some chromosomes are labelled "from mum" and
| some "from dad" and specific portions from each are
| active. It's all rather complex but where imprinting
| doesn't work right you do get distinct genetic conditions
| (compare Prader Willi and Angleman syndromes).
|
| [0] https://www.genome.gov/genetics-glossary/Genetic-
| Imprinting
| gillci wrote:
| That's fascinating, is such imprinting something that we
| have the technology to control yet - or in the near
| future?
| psychphysic wrote:
| I'm not expert but as far as I know no where near having
| the ability to control it.
| gillci wrote:
| Ah that's unfortunate, thanks for the info. Very
| interesting to think about the possibilities of the far
| future anyway.
| anon291 wrote:
| This won't work. Male genomes are imprinted to form a
| placenta. For example, when embryos receive two sets of
| genes from a male and none from the female, they turn into
| molar pregnancies (a giant, aggressive placenta). Embryos
| receiving both set from a female and none from a male do
| not form a placenta and can't implant.
| psychphysic wrote:
| There is a wrinkle, genetic imprinting.
|
| You can put a woman's X chromosome in a sperm but it'll be
| labelled "from mum" and not work quite right.
|
| See Prader Willi and Angleman syndrome for examples.
| bastawhiz wrote:
| That's exactly it. You can't get a Y chromosome from two X
| chromosomes.
| [deleted]
| kaptainscarlet wrote:
| Yes, the do require a male to reproduce. That is correct.
| [deleted]
| russellbeattie wrote:
| As soon as we figure out how to choose the sex of our children,
| we as a species are in serious trouble.
| shagie wrote:
| 1984 - https://pubmed.ncbi.nlm.nih.gov/6541168/
|
| > A laminar-flow fractionation method, developed primarily for
| removing dead sperm from human semen, was successfully modified
| to enrich X and Y sperm to 80% purity, and to characterize each
| enriched fraction for individual swimming behavior. Y-sperm
| fractions were rapidly detected by fluorescent cytogenetic
| staining. Subsequently, the degree of enrichment was
| quantitated with DNA extracted from each sperm fraction probed
| with a human male-specific recombinant DNA clone. In stationary
| fluid, X and Y sperm swam in circles with the same average
| speed. However, in a flowstream, X sperm shifted to a nearly
| straight path of movement in a significantly decreased angular
| velocity. This shift was four times more pronounced in X sperm
| than in Y sperm, especially after the initial transition from
| stationary fluid to flow. The velocity gradient across the flow
| axis was essential for separating X and Y sperm; uniform flow
| velocity did not separate them effectively.
|
| AMA Journal of Ethics - Sex Selection for Family Balancing
| https://journalofethics.ama-assn.org/article/sex-selection-f...
|
| > Currently, there are three available methods for sex
| selection. The first option is prefertilization sperm sorting
| using flow cytometry, which can provide a semen sample enriched
| with sperm that bear the desired sex chromosome. Its accuracy
| is in the 84-92 percent range, and it is not yet available in
| the US [6, 7]. At the opposite end of the spectrum, the most
| extreme form of sex selection occurs after conception in the
| form of elective termination of pregnancy if prenatal testing
| shows the sex of the fetus is the opposite of that desired. In
| certain regions of the world, such as India, such procedures
| are commonly performed, despite being illegal [8, 9].
| tiahura wrote:
| We did that long ago - don't feed the ones you don't want.
| polski-g wrote:
| That has been a possibility since the early 2000's. I read
| about it in New Scientist magazine.
| ectopod wrote:
| The large gender disparity in China's population didn't occur
| naturally.
| smeej wrote:
| No. It occurred by killing female children or aborting female
| fetuses.
|
| That's not the same as creating male embryos deliberately.
| sjducb wrote:
| The Ericsson method has been around since the 70s and works
| pretty well. ~70% chance of getting the sex you want. It works
| because the Y chromosome is a lot smaller than the X so Y sperm
| can swim faster.
| blastonico wrote:
| [deleted]
| illuminerdy wrote:
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