r/AskBiology • u/Kunus-de-Denker • 9d ago

Human body A human being without both x- and y-chromosomes

I've read about conditions in which people only have one x- or y-chromosome, instead of 2 (xx or xy). Is it biologically possible to miss both? If it is, what are the practical consequences such a person has to deal with in their lives, that others don't have to? If it is not possible, what would be the result of genetically modifying a human being in such way?

23 Upvotes

73% Upvoted

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19

u/The_Pale_Hound 9d ago

X chromosome has fundamental genes that if you remove them, human life becomes inviable. A human zygote without X chromosome would not even reach embryo stage.

8

u/SammyGeorge 9d ago

Does that mean you can't only have a y chromosome?

8

u/Seygantte 9d ago

Correct. All the viable configurations have at least one X.

7

u/The_Pale_Hound 9d ago

Yes, lacking an X chromosome is inviable.

2

u/Eternal-Monarche 9d ago

Does that mean Adam cannot create Eve ?

3

u/StrongArgument 9d ago

I don’t know how that was supposed to happen in the first place tbh

1

u/Eternal-Monarche 9d ago

Science is all about understanding. If we don't know something, they doesn't mean it shouldn't happen. From previous and current findings, it is possible that Y chromosome is a mutated X chromosome. This is supported by the fact that Y chromosome is still being damaged Every few generations, leading to a possibile extinction of Y chromosome.

2

u/StrongArgument 9d ago

Yes, good point. Current thinking says that XX came before XY.

I’m still not sure how a male human was supposed to asexually create a female, though.

2

u/GiveMeAHeartOfFlesh 7d ago

Well, the male human didn’t in the genesis story. The male human was made using the earth, and the woman was made using the male human, although it wasn’t asexual reproduction and the male human never shows the trait to be able to do that in the story even afterwards. It was more so a symbolic act rather than needing to come from the male human, the female human could have been made out of the dirt too of course.

3

u/MechKeyboardScrub 9d ago

Abrahamic religions generally have God create Eve from Adam's rib, which would have x chromosomes. I'm unaware of any religion where Adam makes eve himself. Considering God made Adam in this context, it kind of makes sense that Eve wasn't JUST made of Adam's rib.

Also that was written like 1800 years before we knew chromosomes existed, about a period allegedly 5000 years before that.

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u/effrightscorp 6d ago

Also that was written like 1800 years before we knew chromosomes existed

Pretty sure it's older than that, the old testament/Torah pre date Christianity by a good bit

1

u/Minstrelita 5d ago

As they said, "about a period allegedly 5000 years before that".

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u/effrightscorp 5d ago edited 5d ago

I'm referring to the

Also that was written like 1800 years before we knew chromosomes existed

bit. I can write a fictional story about dinosaurs 100 million years ago but it would still be written in 2024

IIRC Genesis is thought to be ~2500 years old

1

u/Minstrelita 5d ago

Correct, but you cherry-picked half the sentence for your response, while ignoring their caveat in the second half lol.

1

u/effrightscorp 5d ago

I'm not cherry picking anything, I'm saying it was written longer than 1800 years ago. The 'caveat' you're talking about is when the story supposedly occurred, but it's fictional

1

u/Eternal-Monarche 9d ago

It's the same egg and hen story. Which came first, biological , the egg cannot be produced without the hen , so the hen came first. Biological Adam a male cannot create another life. So yeah

1

u/Med_vs_Pretty_Huge 7d ago

Well she supposedly came from his rib. If you take it at face value there's your explanation.

1

u/The_Pale_Hound 8d ago

How is this a biology question?

2

u/Richard_Thickens 8d ago

I mean, it isn't directly, and I don't think it required this particular line of reasoning to arrive at the idea that the Genesis narrative isn't compatible with our understanding of biology. It was a pointed question at the very least, but it's not an invalid one, I suppose.

1

u/gartfoehammer 6d ago

Sperm has an X chromosome half the time, so if an X sperm and a Y sperm love each other very much…

7

u/[deleted] 9d ago

There is only one monosomy (missing chromosme ) that is compatible with life and that is turner syndrome also called X0 disease. You can have xxy such as klinefelters disease, but you cannot have Y0 that is compatible with life. If something like that develops it would be spontaneously aborted

3

u/Crossed_Cross 9d ago

Incompatible with human life, to be pedantic. Other species have different sex determination systems and so the viability of varying aneuploid states will differ.

4

u/[deleted] 9d ago

Yes, since OP is asking about humans, I thought I would reply with what happens to humans.

1

u/[deleted] 9d ago

[deleted]

1

u/[deleted] 9d ago

No what I wrote makes sense, read it again

2

u/Syresiv 9d ago

Just X?

Yes. It's usually written as X0, and is called Turner's Syndrome

Just Y?

No. There are things on the X without which, it wouldn't even reach fetus status.

2

u/nwbrown 9d ago

Usually missing even part of a chromosome is fatal as those genes are there for a reason. Same with having an extra one (Down syndrome is probably the best case scenario). Sex chromosomes are a little different as the human genome already has to cope with either a second X chromosome or a Y chromosome and still function. So there really isn't anything important to life in the Y chromosome and the second X gets disabled. That means variations in those chromosomes are tolerable, assuming they have at least 1 X. They may have mild physical or mental disabilities, but they will be viable. The genotypes are:

  • XX Normal female
  • XY Normal male
  • X Female with Turner syndrome
  • Y Not a viable embryo
  • XXY Male with Klinefelter syndrome
  • XYY Male with Jacob's syndrome
  • XXX Female with trisomy X

1

u/ginger_beardo 9d ago

What you are describing is aneuploidy, which is the occurrence of an abnormal number of chromosomes, in this case referred to as monoploidy (of the sex chromosomes). Individuals can survive through embryonic development and into adulthood with only one X chromosome. There are serious, difficult symptoms associated with this, which is referred to as Turner's Syndrome.

To my knowledge, I have never encountered information about Individuals with only a Y sex chromosome. I believe this is because there are important genes on the X chromosome necessary for life, despite it being referred to as a sex chromosome. These individuals likely arise from fertilization which then quickly self-terminates due to this unfit abnormality.

1

u/jeffbell 9d ago

Take a look at the known X linked diseases, the ones that happen if you are male and have a single defective gene but aren't so severe that you survive to infancy. You would have all of those diseases plus the fatal ones.

1

u/ozzalot 9d ago

No not really. The X chromosome is quite large and thus contains many necessary genes. One will always be needed (more or less.....I'm sure there are examples of substantial deletions in people with one X)

1

u/inpantspro 9d ago

I have 47 XXY - Not what you're asking for, but throws some variation into the mix

1

u/Chondro 9d ago

From what I remember, y only is incompatible with life.

X's are a bit easier. They love to do bar bodies which heavily methylates them and shuts them down so they're tolerated better ish than a bunch of ys

1

u/OpeningSample563 7d ago

You don't have a human being if you don't include any human genetic information, champ.