A call out to Geneticists / Biologists

[BelaLugosisShed]

On twitter last night and a poster ( Female, gender critical) claimed that human ova actually have a complete set of sex chromosomes rather than half - ‘23 in the outer layer and 23 inside’ and that we don’t actually need Male sperm to reproduce . She claims that it’s a big conspiracy that silences research.

Does anyone know if what she says is even partly correct / not some possible genetic mutation etc. ?
It sounds like science fiction.

merrymouse the immaculate conception refers to Mary who was conceived without original sin, not the virgin birth

It "puts a spin on the egg"? What? Like a teeny tiny centrifuge?
I sometime wonder how people think the world actually works.

Bela

My goodness, that is some top quality pseudoscientific babble, there.

we don’t actually need Male sperm to reproduce

She claims that it’s a big conspiracy that silences research

I think you need to turn up your bullshit filter, OP. People this nutty are not worth engaging with.

I have a biology degree
I suspect she's talking about mitochondrial DNA, in the "outer layer" cytoplasm. Mitochondrial DNA is only passed down femal line because sperm cells don't carry them, too small. They are discrete from the cells nucleus, have own DNA and act as little batteries that power the cell. They certainly wouldn't fertilise the nucleus, so yes i call bs.

I did work down the corridor from a lab that focussed on genetic imprinting.

That's good enough for me.

Mitochondrial DNA, belonging to the mitrochondria

I’m an academic developmental geneticist. Second meiosis (where the full genome is split into half) happens late in eggs. It happens before fertilisation though, and we definitely need a sperm to create another human.

It’s just a bit odd to see an otherwise sensible Woman throwing out such bizarre statements.
I have had to put an alarming number of gender critical Women right on the ‘all embryos start out Female’ though

It’s pointless arguing with TAs about it - they do love their fake science !

Also a scientist. One currently boggling at those tweets. My eyes.

Anyway. Almost certainly she’s referring to the two polar bodies which are thrown out of the egg at different stages of development to reduce the chromosome content of the egg down to match the sperm. If we didnt, each generation would increase its genetic content such that we’d all have a billion chromosomes in every cell by now. Which wouldn’t be a good thing.

How you extrapolate from that to ‘we don’t need sperm and it’s all a big conspiracy’ I can’t shed any light on I’m afraid.

Should have said that sperm cell has mitochondria but only in the tail which is shed at fertilisation. So the mitochondria in the ovum are the only ones passed on. The mitochondria have their own DNA, which is distinct from the nucleus... where the chromosomes are. Sperm and egg cells are both called haploid cells, have half chromosome number 23, combine to make 46. The mitochondria have their own DNA.

I see it more as a very extreme arm of feminism - the genuine men haters/consensual sex is rape/etc.

There are very easily predicted evolutionary paths to not requiring men for reproduction. Most obviously, a jump of the SRY (‘Make man’) gene to the X chromosome. This would still give us sexual dimorphism, but genetically we would be homogenous (all XX). Less obvious to me that females would become parthenogenic.

LadyScience I agree - polar bodies.

Yes, MaidOfStars, agree.

Not to mention uniparental disomy and the resulting genetic disorders.

Cross post of mutual agreement

Females are born with all the ova they will ever have, all a single X chromosome.. unless in the event of a very rare anomaly. Sperm cells are constantly produced, have either x or y so sperm are the factor determining sex. All ova have potential to result in either male or female, depending if an x or y sperm fertilises

Absolute rubbish.

What a great topic for discussion! I love the fact that there are so many knowledgable women here (as well as slightly dismayed at realising this is another thing to add to the list of stuff I learnt at medical school and have since forgotten ) but enjoyed getting immersed in the incredible things are bodies do at such a minuscule level! Never knew Prader-Willi syndrome was the result of uniparental disomy though!

Our not are

Prader Willi is caused by one region of chromosome 15 being expressed entirely from Dad (most obviously uniparental disomy but also from more subtle imprinting defects). The same region expressed entirely from Mum (same genetic mechanisms) causes Angelman.

Perhaps the tweeter got her information from this multi-part blog series:

Dudes Are Doomed (Part I): The Y Chromosome

I'll admit to finding this series of posts fascinating. The poster is actually very careful about the scientific claims she makes, and references her sources. She definitely writes from a position of man-hatin' though.

As an aside, I do think there is something of a conspiracy of science to obfuscate the facts in order to uphold patriarchal ideas. This paper illustrates the point very well

When does second meiosis occur? I’ve googled but it’s not very clear, is it a pre-stage of ovulation ( for want of a better term ) at ovulation or when sperm begins entry ?

Eggs are pretty much all the way through second meiosis before fertilisation. It’s fertilisation that finishes it.

But the first meiotic division is not equal. There is already a Half A Genome destined to be lost. It’s ferilisation that triggers the loss.

Wow, what a fascinating thread. I wish I went onto uni and such to actually..learn stuff rather than buggering off abroad to do a job where I could just get pissed 24/7 instead as it seemed the fun option