#sex chromosomes

[birdgenetics]

This just in! What I learned today:

I was doing some reading on cat genetics and I learned female mammals undergo X chromosome inactivation! In each of their cells they randomly inactivate one X chromosome to prevent overexpression of the X chromosome. That's how you get the magnificent tortie cat. In some pigment cells the Orange chromosome is active and in the others the black is active.

So that made me wonder, do male birds (with the ZZ sex chromosome arrangement) do Z chromosome inactivation to prevent overexpression of the Z chromosome? Sexlinked colors do seem to work differently in birds.

And I discovered, NO! This really does explain a lot.

Take Sex-linked Dilution, for example.

Female geese have one Z allele so they have one copy of the dilution, therefore, they are a slightly lighter gray than wild type and have a little white.

Heterozygous male geese have a copy of the dilution and a copy of wild type. Since they have one dilution allele like the female geese, they are the color of the female geese.

But Homozygous males have a double expression. They have two copies of the dilution and they are mostly white with a little bit of light grey.

You see the same in faded pigeons. Hemizygous females and heterozygous males are the same color, Homozygous males are lighter.

In barred chickens the same thing, dark hemizygous females and heterozygous males, light homozygous males.

But before you get too comfortable there is a twist.

There is another goose gene that is so rare I forgot to show a photo of it in my last post where I said I showed all possible goose alleles. (Actually, I believe it might not actually be all that rare and might just be the "weird swan goose white" I mentioned.)

Aqua Discovered by Snyder's Waterfowl.

Hemizygous females and homozygous males are white. Heterozygous males have this blue spotted color.

A more common example would be ash red pigeons. Hemizygous females and homozygous males are ash red but heterozygous males are mostly ash red with a few blue/black flecks.

Why is it like this? Incomplete dominance, I guess wild type and white want to battle it out, I honestly don't know.

And of course recessive sexlinked genes like Chocolate or Dilute pigeons need the bird to be hemi or homozygous to express. It really makes me curious about what other genes are sexlinked in mammals and birds and how they looked.

[cbcbiology]

Once again for all y'all who are "but biological sex--"

BIOLOGY: IT'S COMPLICATED.

What the fuck

[liberalsarecool]

Context.

[tenth-sentence]

Von Winiwarter explained the sexual difference by arguing that while the human female had two sex chromosomes – a double X – the human male must have only one, a single X.

"In the Name of Eugenics: Genetics and the Uses of Human Heredity" - Daniel J. Kevles

[botanyshitposts]

dichotomous plants are so weird man. like they’re not even weird it’s the becoming the dichotomous that’s weird. i went to a talk once about a population of strawberries that were accidentally slowly becoming dichotomous and they didn’t even have sex chromosomes, like they had like a bunch of genes across a bunch of chromosomes that did a little bit of sex but not a lot and it added up to one whole sex kind of but not enough that they had all collectively decided to be one sex or the other, so there was still like, a sizable chunk of the population that was producing flowers of both sexes. like they were microdosing it. taking the sex genes for a spin in the strawberry patch

[mollymaclachlan]

the conservative party starting off pride month by promising to rewrite the equality act to exclude trans people from sex-based legal protections is so depressingly predictable and I fucking hate this country

[existennialmemes]

If you're visiting family for Easter, and they won't respect your gender, remind them that Jesus's chromosomes are canonically XX, as he inherited all of his human DNA from Mary.

Unless of course they think that Mary was actually a child-bearing XY cis woman, which is also a delightful and realistic possibility. So either Jesus is Trans or Mary is Intersex.

Or it could also be both!

Happy Easter Day of Trans Visibility!

Further reading on that if you're interested:

[elektroskopik]

JFC, we learned about Intersex people in High School and all of the weird, funky things that can cause chromosomal disorders or issues with genetics that result in hormonal variations and weird gene expression.

🤣🤣🤣🤣🤣🤣

[narrator-navigator-storyteller]

to my fellow intersex people yearning for representation in characters: while you are waiting, you can make any fictional character you want intersex the government can't stop you. "they don't have [stereotypical intersex trait]" cool a lot of people don't. and also you can just give them to them. i gave a fictional guy gynocomastia because i wanted to. just intersex those guys. inter their sex nobody can stop you.

this is a hostage negotiation situation. for every show you make with no intersex rep we will make it have intersex rep.

[mr-selfdestruct]

Why do biology teachers never mention intersex people.

[the-commonplace-book]

Trump wants to enforce gender assignment at conception based on biological sex. AFAB and AMAB are out. Absolutely every single American will now be AFAC (assigned female at conception). Congrats on the gender.

[riagraie]

Bro some people online make me so mad.

WARNING: THIS POST DISCUSSES GENDER AND SEX(in terms of biological gender)

"if you have a Y chromosome, your male"

ERMMMMMM actually, you can have a Y chromosome and be female. You can also have just X chromosomes and be male!!!

Genetics people!! Crossing over is real! And in rare cases, you can end up with multiple different chromosomes which alter what genitalia you do or don't develop!!

The norm is males have XY and females have XX. But you can also end up with most known (not most common) combos like XXY, XXX, XO, and XYY. AND GUESS WHAT???

THEY CHANGE WHICH SEX YOU PRESENT TO BE!!!

When it comes to biological sex, you can be male or female based on what genitalia you have and develop. In very rare cases, you can have both types. But overall, in a biological sense, male and female.

GENDER DOES NOT EQUAL SEX!

In this sense, Gender is a spectrum, and depending on your PERSONAL IDENTITY, you may be BIOLOGICALLY male but feel female and so on.

GRRRAAAAHHHHHHH

THESE DUMBASSES ON THE INTERNET TRYING TO SAY ONE THING OR ANOTHER MAKE ME SO MADDDDD

If your going to rant and rave about something online as touchy as this, know your facts. Don't be that idiot who spreads misinformation. Because then, your part of the problem. Your part of the plague of hate spreading across the globe.

Oh and as a disclaimer, I am a cis female who paid attention during my intro to biology class in college and did self guided research because I love genetics.

I am in no way posting this to be transphobic or to promote hate. I am not transphobic and am a straight ally for the LGBTQIA+ community.

I am posting this because it's so important to be informed and to use your knowledge to inform other people.

[truthwithlight]

diversity win the us government just accidentally made everyone female!

[sapphic-boy]

"yeah you may be bigender but you're BIOLOGICALLY-" im biologically both of my genders too actually, my primary and secondary sex characteristics are a mix of male and female due to hrt and surgery thank you very much

[fearecia]

Y'all, I'm dying over here. Just laughing my ass off. I went and read the whole thing about sex and whatnot that Trump is putting out for the federal government.

THIS is how they are defining male versus female:

But see, here's the thing. They are specifying AT CONCEPTION...

Everyone is "female" at conception.

From pubmed...

From NCBI:

https://www.ncbi.nlm.nih.gov/books/NBK222286/#:~:text=During%20early%20development%20the%20gonads,the%20development%20of%20the%20testes

Here's a fun little article about disorders that make it so that people who would otherwise develop male characteristics instead end up growing up as women...

(What's really "funny" here is that while there are disorders that result in folks with XY chromosomes growing up appearing like they have XX chromosomes... There are NO disorders that do the inverse... Least none that I'm aware of/could find. PCOS is the only thing that comes close, but that isn't the same as your body not generating the organs that match your genetics).

In summary, their goal was to keep "men" out of the "women's" restroom.

They've just said that everyone must use the women's restroom.

[obaewankenope]

You know... All this hatred Jk Rowling has for transfolks and her doubling-down on gender being an X or Y science thing... It would be beyond hilarious if Rowling did the chromosome test and found out she had one of those rare chromosomal variations (like Klinefelter Syndrome: XXY chromosomes, or Swyer Syndrome: females with XY chromosomes) that meant she wasn't a "real" woman by her own standards of XX only lmao

Like, I feel like that would be fitting for the woman who stirs up so much transphobia and goes on and on about male on female violence about the Olympics and then tries to double-down on it not being about the athlete directly but "obviously" it's a more general thing and how it looks and blah blah

Just... Hey Joanne. Joanne, hey. Why don't you do the DNA test and release the results and show us your chromosomes? Give us that very private information in a public sphere on the internet where nothing really dies to prove you're really a womanly woman. Hmm... No? Odd how you don't want to do that but demand someone else should.

Gods I fuckin hate her