#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.

[blatentmisinformation]

There are only two chromosomes, total. All other "chromosomes" in any organism are just variations of the X and Y chromosomes made by sticking genes together.

[neosciencehub]

Groundbreaking Discovery: Octopuses May Hold the Record for the Oldest Known Sex Chromosomes

Groundbreaking Discovery: Octopuses May Hold the Record for the Oldest Known Sex Chromosomes @neosciencehub #Octopuses #SexChromosomes #sexdetermination #cephalopods #Mystery #neosciencehub #Sciencenews

Recent research has unveiled a remarkable finding in the world of cephalopods: octopuses may possess the oldest known sex chromosomes among animals, with origins tracing back over 480 million years. This study, conducted by a team at the University of Oregon and published in “Current Biology”, marks a significant milestone in understanding genetic sex determination in these fascinating…

[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

[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.

[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:

[haggishlyhagging]

Natalie Angier's research for her book, Woman: An Intimate Geography, confirms that "in the basic biological sense, the female is the physical prototype for an effective living being. Fetuses are pretty much primed to become female unless the female program is disrupted by gestational exposure to androgens." The Institute of Medicine study describes how our sex begins in the womb, and how the female is the primal matrix:

All human individuals—whether they have an XX, an XY, or an atypical sex chromosome combination—begin development from the same starting point. During early development the gonads of the fetus remain undifferentiated; that is, all fetal genitalia are the same and are phenotypically female. After approximately 6 to 7 weeks of gestation, if the fetus is male, the expression of a gene on the Y chromosome induces changes that result in the development of the testes. In contrast, fetal ovarian secretions are not required for female sex differentiation.

David Crews, of the University of Texas, describes the female as "the ancestral sex, while the male is the derived sex." Angier writes, ". . . eggs are inherently female. So in thinking about mirrors into infinity, the link between mother and daughter, the nesting of eggs within woman within eggs, we can go a step further and see the continuity of the chromosomes. No maleness tints any part of us gals, no, not a molar drop or quantum." There is no maleness in female- XX people, literally, and the culturally ascribed gender categories of masculine and feminine are clearly invented. Thus, females have no "masculine" side, as Freud or Jung would have us believe. This is just patriarchal gender jargon within a patriarchal frame.

If you are female, you have XX chromosomes in every cell. This is reality, a fact, not a belief or opinion, not a theory, not a feeling.

-Ruth Barrett, "Eve Was ‘Framed’" in Female Erasure

[mr-selfdestruct]

Why do biology teachers never mention intersex people.

[bookmothic-dyke]

Tetrads, the DNA that fucks.

[arabella377]

i was chilling until i found out about this fella

[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!