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Scientists generate XX and XY cells from a person with Klinefelter syndrome
- koollman 4y ago
- 323 4y agoIn 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 4y agoWould the DNA not describe the cell it belongs in?
- 323 4y agoNot 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 4y ago"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 https://en.wikipedia.org/wiki/Paternal_mtDNA_transmission
- tibbydudeza 4y agoAfaik 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 ???.
- njarboe 4y agoFrom the Wikipedia page (read the original source for details): The controversy about human paternal leakage was summed up in the 1996 study Misconceptions about mitochondria and mammalian fertilization: Implications for theories on human evolution, which was peer-reviewed and printed in Proceedings of the National Academy of Sciences.[15] According to the study's abstract: In vertebrates, inheritance of mitochondria is thought to be predominantly maternal, and mitochondrial DNA analysis has become a standard taxonomic tool. In accordance with the prevailing view of strict maternal inheritance, many sources assert that during fertilization, the sperm tail, with its mitochondria, gets excluded from the embryo. This is incorrect. In the majority of mammals—including humans—the midpiece mitochondria can be identified in the embryo even though their ultimate fate is unknown. The "missing mitochondria" story seems to have survived—and proliferated—unchallenged in a time of contention between hypotheses of human origins, because it supports the "African Eve" model of recent radiation of Homo sapiens out of Africa. [15] Ankel-Simons F, Cummins JM (November 1996). "Misconceptions about mitochondria and mammalian fertilization: Implications for theories on human evolution". Proc. Natl. Acad. Sci. U.S.A. 93 (24): 13859–63. Bibcode:1996PNAS...9313859A. doi:10.1073/pnas.93.24.13859. PMC 19448. PMID 8943026.
- LesserEvil665 4y agoI am eagerly anticipating the birth of Henry Lacks.
- elektrontamer 4y agoHaha, pretty good one! Incredible that her cells are still used all over the world long after her death.
- kingkawn 4y agoThe 70-90 chromosomes of the HeLa line may not agree to this easily
- davidguetta 4y agoDumb question but how is this different from a women giving birth to either male or female babies ?
- skadamou 4y agoI 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.
- hammock 4y agoWomen require a man to contribute before they can give birth
- vjerancrnjak 4y agoYou 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 4y ago
- psychphysic 4y agoIt 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 https://www.genome.gov/genetics-glossary/Genetic-Imprinting
- skadamou 4y agoInteresting. 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?
- hammock 4y agoNot 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?
- deleted 4y ago[deleted]
- _Algernon_ 4y agoYou'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 4y agoI’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_ 4y agoFair enough
- bioemerl 4y ago
- blastonico 4y ago
- illuminerdy 4y ago
- deleted 4y ago[deleted]
- 752963e64 4y ago
- walnutclosefarm 4y agoWhat 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 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-male-half-female https://www.birdnote.org/listen/shows/cardinal-thats-half-ma...).
- fallingfrog 4y agoFYI I'm pretty sure you meant to link a different nature article, the one you linked is something about methane emissions from wetlands.
- michaelsbradley 4y agoparent seems to have fixed it: by following the link, I got an article titled A Cardinal That's Half Male, Half Female.
- walnutclosefarm 4y agoThanks for catching that. Fixed.
- pavlov 4y ago
- mbg721 4y ago
- photochemsyn 4y agoOne 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 https://jbiol.biomedcentral.com/articles/10.1186/jbiol95
- hinkley 4y agoSo 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.
- deleted 4y ago[deleted]
- shagie 4y ago> > 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 https://en.wikipedia.org/wiki/X-inactivation ) even has a picture of a tortoiseshell cat.
- colpabar 4y ago
- zoklet-enjoyer 4y agoNothing
- at_a_remove 4y ago
- birdsink 4y agoIt'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.
- tosc 4y ago
- kingkawn 4y agoIt 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 4y ago"They made me do it!" -- every abuser ever.
- kingkawn 4y agoincoherent comparison, as expected
- StevePerkins 4y agoIs this basically the approach speculated by Neal Stephenson in Seveneves?
- Ygg2 4y agoNot really, they didn't all have Klinefelter's syndrome.
- russellbeattie 4y agoAs soon as we figure out how to choose the sex of our children, we as a species are in serious trouble.
- ectopod 4y agoThe large gender disparity in China's population didn't occur naturally.
- smeej 4y agoNo. It occurred by killing female children or aborting female fetuses. That's not the same as creating male embryos deliberately.
- tiahura 4y agoWe did that long ago - don’t feed the ones you don’t want.
- sjducb 4y agoThe 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.
- polski-g 4y agoThat has been a possibility since the early 2000's. I read about it in New Scientist magazine.
- shagie 4y ago1984 - https://pubmed.ncbi.nlm.nih.gov/6541168/ 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-family-balancing/2014-10 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].
- verdenti 4y ago
- version_five 4y agoThe 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?
- deleted 4y ago[deleted]
- cjtrowbridge 4y agoThe 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 4y agoFrom 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?
- cjtrowbridge 4y agoIt is. And that quote is correct. There's two problems here. One is that XX/XY is not even a majority of the common human chromosome karyotypes, and changing karyotypes does not change someone's sex characteristics; those are determined at one specific moment during gestation, which may or may not be affected by changing the chromosomes beforehand, but certainly would not be affected by changing their chromosomes after that moment. Primary and secondary sex characteristics are determined by androgen metabolism, not by chromosome karyotypes. Secondly most of the human karyotypes are not assigned a sex until some time after birth, and XY is often assigned female at birth because the divergence of homologous structures depends on androgen metabolism, not chromosome karyotype. Sex and gender don't exist for cell lines in the same way they do for people. TL/DR; This is an article about a study that found they could change a cell line's karyotype, not a person's sex characteristics which are determined not by chromosome karyotypes but by androgen metabolism during gestation. Whoever wrote the headline didn't understand the topic.
- einpoklum 4y ago> 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 4y agoHmm. 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 4y agoFrom 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"
- dang 4y agoOk, let's go with that. Thanks! None of us will have heard of Klinefelter syndrome before, but maybe that's a good thing.
- verdenti 4y ago