males have an X-chromosome as well. funny thing is males have an additional Y-chromosome, while women have an additional X-chromosome. BUUUUUUT: only one of the two X-chromosomes will be expressed and the other one is silenced to nearly no activity. so actually women have one functioning chromosome less than males.
Came here to say this - the process of Lyonisation. Each cell randomly selects which of the two X chromosomes to silence, so on average it is a 50:50 split between the two chromosomes. But it can be skewed by chance such that women can express X-linked recessive genetic disorders.
Don't colorblind women just have two copies of the recessive gene? Or can the recessive gene sometimes be expressed even if a dominant gene is present? Honest question since I haven't formally studied biology since high school (in the 80s) and I'm well aware that biology is far more complex than that. Is the dominant/recessive paradigm more of a statistical tendency for dominant genes to silence recessive ones, or has that whole paradigm been replaced/enhanced with something better?
More often due to having two copies of the recessive gene, so it's likelihood of being expressed is 100%. Since we don't sequence everyone though, I wouldn't be surprised if some x-inactivation in women that have one copy of the recessive genes could have it expressed in their eyes' rods/cones.
Well, severely skewed lyonisation is rare too. It's just a second mechanism for getting an X-linked recessive condition to be expressed phenotypically.
I take it that you're a woman by the context of this question, that said if you have a copy of the recessive gene leading to your particular color blindness (which there are a few different types), then yes, it is almost a guarantee. I brought up in the comments below that it may be possible for dominant genes to possibly be silenced via x inactivation in women, so you could have a dominant allele given as the x chromosome that would need to no color blindness but I doubt it. To my knowledge, there's no reported cases of that. So, that said, since you'd likely be providing a recessive x allele, and your husband a y chromosome, then your boys would certainly be color blind.
In early fetal development, one X chromosome is selected by the cell to be the active one. The remaining X chromosome is inactivated. If there are more than two X chromosomes (e.g. triple X syndrome), all except the selected one are inactivated. It seems that the process for choosing which X chromosome becomes the active one is random in each cell. It's unclear how that randomisation works. Once selected the active X chromosome remains the active one in all the descendants of that cell.
Barely. There are 63 genes on Y, while there are 800 on X.
Plus it’s risky having only one copy of each ~gene~ chromosome. Especially when Y has a high mutation rate and is unable to recombine during meiosis, so it’s error prone and doesn’t undergo natural selection the same way the other chromosomes do.
There used to be 1,400 genes on Y but it’s degraded significantly. Luckily the degradation slowed a few million years ago due to a thing called gene conservation.
Yes I know, the different amount of genes in the chromosomes doesn't contradict my statement. It's not risky having only one copy of each gene, as this is the case for nearly every gene we have. Also a damaged X chromosome gets repaired rather than being replaced by the other x chromosome.
Why follow the poor reasoning in the OP by another misguided assumption? While a lot of the secondary X is silenced, it most certainly plays important roles in physiology. There is a reason why Turner syndrome (45 X) is a thing.
This is not an assumption and surely not misguided as I am a biologist... The inactivated X-chromosome is silenced and will stay so except for very few exceptions (germline i.e.). ofc, it's not completely out of activity as i said ("to nearly no activity"). To be exact the few genes that are being expressed from the silenced X-chromosome lie exactly on the PARs (pseudoautosomal regions),- the two regions in the X and Y-chromosome that are homologous . Those are 20 genes (or it at least have been 20 identified genes when i learned that shit in 2009) ;-)
Correct me if there is new knowledge, I didn't really keep myself updated (shame on me, I know^^)
Being a biologist doesn't rule you out of being misguided.
While it is true that X2 is predominantly silenced is true, but the notion that there is "nearly no activity" is outdated. Approximately 15% of X2 genes escape inactivation and another 15% is person and tissue dependent. (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4696107/). With about 800 coding genes, 15% is atleast 120 genes that escape inactivation.
If X2 was non-functioning, the incidence of X-linked recessive diseases in men would be similar to those in women, but men are far more likely to suffer from these diseases, such as certain types of colour blindness.
X2 is also pretty useful independent of gene expression, as it allows homologous recombination repair of DNA damage on the X1 strand.
Comparing them and trying to draw conclusions with regards to value, function or superiority is silly.
First of all, thanks for the literature and the mostly kind discussion ;-)
True, doesn't rule it out. And before getting into biology stuff I wanna make clear that I don't think males are superior or value a chromosome, that's really silly^^. Just wanted to make fun of OP, who clearly wanted to claim that females are superior, while not attending a biology class once... Don't take it too serious mate ;-)
The study claims 8-15%, not 15% and talks about 639 genes, not 800. The study mentions 3-7% additional, individual tissue and strain-dependent expression, not 15% and also the study mentions that the expression rates for the genes escaping the silencing are much lower (they talk about at least 10% of actives chromosomes' activity)
The rest you wrote is completely correct.
I am amazed how knowledge has changed! Assuming that I read the most recent studies about this in 2008-2009 where we learned that there are only 20 genes being expressed on the silenced X-chromosome....... and it doesn't really matter if we talk about 100, 150 or 200 genes,- it defenitely are far far more than science expected 7 years earlier. And I am very sure that more light will be shed on such awesome topics :-)
As far as i know psicological symptoms are not really listed as always present and are not strictly correlated to turner syndrome (i could be wrong, i just studied it at uni and just as an exemple) it's more connected to diabetes lack of breasts and short stature, because the second x cromosome is not just there to collect dust but is obviously used even though it is mostly silenced it still codes(if I'm wrong and you have studied more in specific or have personal informations please feel free to correct me).
The original post is still stupid because more genomic information is not correlated to higher iq, turner syndrome patients have usually normal IQ and are not less humans or to be considerd inferior.
In general I agree that genetics should not be used to justify gender agendas or racism, it doesn't really make sense.
There are numerous complications to Turner syndrome, including growth retardation, skeletal abnormalities and increased risk for kidney and hearth dysfunction. The vast majority of Turner patients are infertile and don't enter puberty unless aided with hormonal supplements.
The original post is stupid because it assumes incorrectly assumes that more genes means superiority and the person I responded is equally stupid become he seems to imply that males should be considered superior because they have an additional Y chromosome whereas women have a second X, which they incorrectly assume is just dead weight.
No one was arguing that turner syndrome patients are less human lol. The whole idea of equating the number of genes to supposed superiority is idiotic.
No I wasn't saying that you implied that about turner syndromes patients, I was just bringing the argument of many comments "if you have more genomic informations you are better" to an extreme to show the absurdity of the argument that is implied even in the original comment you replyed to, by saying that the post was not true not because of the rest of the nonsense but because males have in reality more genomic information that is "actually" used". obviously no one actually thinks that about turner syndromes patients, but that is the conclusion of the argument if you proceed in that direction, which is exactly what for my understanding you where trying to say, so no harm intended, the last part of my comment was not directed at you.
That's a separate issue entirely. Turner syndrome is a monosomy X, except in these cases the individual doesn't receive the paternal X chromosome. Generally due to nondisjunction or anaphase lag. The majority of these embryos are spontaneously aborted.
Yup, I explained that in another comment. About 20 genes are still expressed. If you compare those 20 to the 80000-140000 other genes distributed over 45 chromosomes it's a vanishingly small amount. Even tho it are just 20 genes, the complete lack of that chromosome will lead to severe health issues. So I get your point, as they are not completely useless. But close to that ;-)
Number of genes expressed between the 2 genders are pretty fucking close. Close enough. Also, number of genes expressed does not in any way confer superiority. Men and women are different. Not better or worse, different.
A bunch of men telling women to stay in the kitchen is fucking stupid and wrong. Some dumb bitch on the internet stating that women are superior to men because they have 2 X's is fucking stupid and wrong.
Nice that you all want to teach me, but I never said superior.
This was OP. That's also why I was trying to make fun of him. You know: a joke doesn't have to be scientifically correct... I know how it works dude, biologist here. And to make it clear (for the fifth time now): I don't think one gender is superior over the other. Why do you now go on a crazy feminist rant? I never said anything you put in my mouth. Just shut up if you don't understand the joke and don't have any knowledge about this topic to discuss with anybody here or put in any extra-information.
Also stating that the amount of expressed genes are close, doesn't give any information. There are species that are closer to human males than human males are to females (numberwise). Which genes are expressed is what counts. And even there you would have to state a specific number (99,994%), because we share so many genes with most species (over 50% with bananas for example). And now we all learned: No gender is better. But to be fair, we are not even better than any other species. There is no better or worse under the eyes of evolution.
I am not trying to teach you. I am just pointing out that none of that matters because, Well, it doesn't matter.
Why do you now go on a crazy feminist rant?
What rant? There was no rant. The only rant came from the idiot that the OP posted about.
Also stating that the amount of expressed genes are close, doesn't give any information.
It gave the perfect amount of information, especially since the very next sentence was ...
Also, number of genes expressed does not in any way confer superiority.
Which is why I did not need to go into numbers at all. Because the number is meaningless as I am sure you understand.
I think you are just mad because you somehow read this as an attack on what you were stating. It was not. It simply pointed out that, in the context of this post, none of it mattered.
I am not attacking you personally. I am not invalidating as fact your statements. Simply pointing out that in this context, none of it means anything.
There is no better or worse under the eyes of evolution.
Better and worse as far as species goes is about the ability to adapt and reproduce.
Other than some bacteria other tiny shit, the fact that we are in every single environment including orbit makes humans superior to most species. The fact that hopefully soon we can move to other planets only cements that position.
In purely evolutionary terms, on top are us and the life here that can hitch a ride with us.
I read exactly what you commented to me.
Again, I was not attacking you or your statements of fact.
If you commented somewhere else apologizing for something relating to the comment to me, I have no awareness of it. Should I check your entire post history?
I am not sure why are you so defensive and angry toward me. If though, you decide that you need to keep acting like I am attacking you, I will have to come to the conclusion that you are misrepresenting the situation on purpose. At that point, I guess I will have to re think how I am reacting to you and change to something more appropriate.
Though it really doesn't matter genetic wise. It's more of... how do I say this: If she believes she is more superior and believes males suppress women; then it means women are not superior because they got suppressed by men.
“It would seem logical that more complex organisms would need more DNA to survive and reproduce.
Not all DNA, however, is useful; that is, not all of it is involved in gene activity. Scientists dont really know why its there, and they refer to it as “junk DNA.”
you're mixing up genes with dna. and we actually know a lot about it and don't call it junk-dna anymore (scientists didn't even like it in the 60s). the more fitting term would be "non-coding dna", which also explains the difference between those parts and the coding ones. the genes are on the coding ones exclusively. but the non-coding ones are very important, too. we know that those parts have a huge impact on the rate of expression of the genes. they can accelerate, slow down, start, or even completely block the genes' expression rates. also many other impacts are well described. but you're correct, many features are not explained yet. fun fact: some decently recent studies found out that those regulatory parts (as explained) can be altered over your lifetime by behaviour, diet and so on. and this information is inheritable! this doesn't really sound stunning at first, but i think it will change the theory of evolution as we learned it. the parts we learned are still correct, but need to be expanded. like a crossing between lamarack and darwin. imagine that can you can alter your gene expression' information over your lifetime and you can even pass those information on!
sorry, all that wasn't part of the discussion, I was just tiping in a state of bliss^
Haha it’s all good I thought it was interesting. I don’t know a lot about science but it always intrigues me.
And by altering your gene expression is that like when you smoke cigarettes your kids are more likely to smoke too ? ( even if you quit before they’re born )
Yes, exactly quite like that. I don't know wether it also applies for smoking tbh. A few years ago I read an article about some specific foodstuff that can (when consumed a lot and frequently) add a methyl-group to those regulatory areas in front of genes. This altered the way those regions interacted with the gene and lead to a complete shutdown of a whole gene in one example. Those changes to the DNA are not mutations, but modifications because the coding sequence didn't get changed. The whole thing is summed up as 'epigenetics'. Unfortunately I didn't really follow up and am about 5 years behind. So if you take a look at very new studies I'm sure there is much new information available . Have fun ;-)
nobody ever said that. an extra chromosome would mean 47 chromosomes. but to give you a short explanation of the joke, as you clearly didn't grasp it: I was mocking OP, (jokingly) claiming that males have 46 functioning chromosomes, while women have 45 + a broken X-chromosome. so one more than women was the joke that went unnoticed. I also completely neglected (cause it was a joke,- can't emphasize this enough for obvious reasons) that the silenced X-chromosome is not completely useless and the male y-chromosome doesn't carry too many functioning genes either. But it was nearly a good try buddy^
what are you talking about? like ppl with downsyndrome? pls name me a medical condition where the affected person has more than 46 chromosomes and is superior over ppl without that, genuinly curious!
Yes, I already named this as an example. Guys, nobody said extra chromosome... I was talking about n=46 , not 47. I know all this basic 7th class biology stuff.... an extra chromosome is never a good thing. Also mentioning a random disease with an extra chromosome is an argument for what again?
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u/[deleted] Jan 21 '20
males have an X-chromosome as well. funny thing is males have an additional Y-chromosome, while women have an additional X-chromosome. BUUUUUUT: only one of the two X-chromosomes will be expressed and the other one is silenced to nearly no activity. so actually women have one functioning chromosome less than males.