27 April, 2012

A-Z Blogging Challenge: X Chromosome

The X chromosome.
Public domain image.
The X chromosome is one of two human sex-linked chromosomes, the other being the Y chromosome.

The X chromosome has around 155 million DNA base pairs, or 1000-2000 genes. 1,098 of those genes code for proteins and consist of around 5% of all the DNA in human cells. The X chromosome is larger and carries more genes than the Y chromosome, which means that if a gene on the X chromosome codes for a disease, that recessive trait will apear in any male children, since there is no dominate gene to counteract it. This characteristic of the X chromosome is visible in the fact only female cats can be calico, for its the females carry the allele for color and it can only code for one color at a time.

Females get two X chromosomes and males an X and a Y; since the normal chromosome count is 46 in total, females are denoted as 46,XX and males 46XY. In all cells other than egg cells, one of the two X chromosomes is inactivated (called Lyonization) except for a small area called the pseudoautosomal region. Many of the genes in the pseudoautosomal region are necessary for human development.

A graphic of triple X syndrome, with a male on the left and female on the right, by
Silver Spoon, CC-BY-SA-3.0. SOURCE.
Problems that can arise from changes along the X chromosome include microphthalmia (deletion of some of the genetic information on the chromosome; results in failure to create the enzyme holocytochrome c-type synthase, which in turn produces cytochrome-c, which in turn is involved in oxidative phosphorylation that allows mitochondria to create ATP), triple X syndrome (also known as 47,XXX and trisomy X; caused by having three X chromsomes), and Turner syndrome (also called 45,X, it is when only one normal X chromsome is present and the second of the pair is missing or changed; occasionally, only some cells are altered, called mosaicism).

A video about genetics, which explains the role of chromosomes and DNA:




And if you want information about the other chromosome, stop by tomorrow--I also explain why there was speculation humanity would go extinct because of the Y chromosome. Just in case that interests you . . .

-----The Golden Eagle


Old Kitty said...

Yay!! I have two x chromosomes! Take care

Anonymous said...

As a member of the OTHER chromosome, ahem, I shall be here. ;)

Traci Kenworth said...


Anonymous said...

You are a genius to have created your A-Z based on science! I bow to you, Golden!

Clarissa Draper said...

I can't believe there is so many syndromes caused from errors in chromosomes.

Noushka said...

Truly interesting!
I bet chromosomes have still many secrets yet to be discovered and who knows how humans will "play" with them in the not-so-far future!!
Thanks for the info!

Matt said...

Another awesome post. Chromosomes make for interesting discussion.

Anonymous said...

Curious question then. In ALIEN 3, the prisoners in the Fiorina 161 penal colony are described as "all male, double-y chromosomes" or 47,XYY. How does that compare/contrast with the 47,XXX or the 45,X or 47,XXY counterparts?

S. L. Hennessy said...

Isn't it weird that one little chromosome can make such a difference? And is responsible for the continuance of our species. Crazy.

Sherrie said...

Fascinating info! Thanks for sharing and thanks for stopping by my place. Have a great day!

Just Books

Madeleine Maddocks said...

Cute x post. I like it. Reminds me of my A level Biology studies eons ago...

~Sia McKye~ said...

One X in the wrong place...there is so much still to learn about all this.


Rusty Webb said...

I'll be sure to stop by tomorrow then.

Pat Hatt said...

So many in the X that surely has to perplex. But extinct as well? I don't want to go to ummm Hell..haha

Yeah so much crap relies on chromosomes it isn't funny, one little nick and you could have a nervous tick.

the writing pad said...

Great X - wondered what you'd do!! Lots of highly digestible info on a very complex subject - looking forward to Y :-)

Alex J. Cavanaugh said...

All I know is I'm happy I have an X and a Y!

anthony stemke said...

Complicated yet interesting. I had heard of oxidative phosphorylation though.
As always, very good post.

Carrie Butler said...

Great work, Eagle! :)

Susan Gourley/Kelley said...

Genetics is one of my favorite parts of biology to study. Can't wait to hear about that 'y' problems tomorrow.

Nancy Thompson said...

Absolutely fascinating, though you lost me a bit there at the end. I shall be back for Y.

Andrew Leon said...

Well, I have nothing really to add. This is such a huge topic, I might not start if I start.

running4him said...

Cool post, ingenious use of "x" to!! All I could think about while reading it though was the tv show x men evolution!! They are always talking about the x gene!! Yes, I know it is different!!!

Donna K. Weaver said...

Hey, brilliant minds and all that. I saw that article, too, about the Y chromosome. I hope they fix it!

Romance Reader said...

It's always fascinating for me to read about the structure of the chromosones.


Baur said...

Very neat! I find these things fascinating!

The Golden Eagle said...

Old Kitty: Me, too. ;)

Stuart: *shakes head* It's all the males' fault. They're not neat and organized with two X chromosomes.

Traci: Agreed. It's an evolving field!

Jack: Aw, thank you! :)

Clarissa: It's scary to think of all the things that can go wrong with chromosomes, genes, and DNA . . .

Noushka: I hope we don't do too much damage experimenting. Though that may very well be a futile hope, since humanity tends to play with fire.

You're welcome!

Matt: Thank you!

They do. :)

Joshua: Funny you should mention that, because I actually talk about 47,XYY in my next post.

But to summarize here, 47,XYY is a male with an extra Y chromosome. 47,XXX is female with an extra X chromosome, 45,X is female with a missing X chromosome, and 47,XXY is male with an extra X chromosome.

S. L.: Yup. Though nature has a tendency to throw in little things like that. :)

Sherrie: Thank you!

You're welcome. It was great to visit your blog!

Madeleine: Thanks. :)

Sia: There is. Who knows what could happen, now that people are capable of altering things on the molecular level.

Rusty: The fate of humanity's on the line!

Okay, maybe it's not that dramatic . . .

Pat: LOL. Multiple syndromes, potential extinction; chromosomes are definitely loaded.

The writing pad: Thank you!

Alex: And I'm content with my XX.

Anthony: It's an interesting cellular process.

Thanks. :)

Carrie: Thank you.

Susan: It's a fascinating subject! Genetics, that is.

Nancy: Hope I didn't make things too confusing!

Andrew: Genetics is a big field of study, especially now with advances in technology.

Running4him: Thank you!

Hey, if it gets people thinking about the topic, no problem. :)

Donna: Cool--it's funny how things on the web get around.

Riya: Same here. They're interesting bundles of DNA . . .

Baur: I do, too. :)

Carol Kilgore said...

I know more than I did before I came here today :)

As much as we know, there's still much we don't. Maybe you'll be the one to figure out some of it.

Happy Weekend :)

Anonymous said...

Very interesting! Yeah, these chromosomes are something else alright. My husband seems to have inherited the one passed through the generations, that likes to burn the toast, as his father did before him and I suspect, his forefathers did before that! So nice of you to post this complicated stuff. So informative. Great! MoonWynd

Susan Kane said...

You ARE a genius, as Jack said!

Genetics are a science that didn't even exist at my birth in 1951. Now, wow! it is amazing.

mshatch said...

I am definitely interested in why 'they' thought humans might go extinct.

Working in a veterinary field I knew the calico cat thing but I still don't understand why they're also called money cats. Hmm, maybe I'll google it...

Jay Noel said...

This is what irritates me with the Twilight Saga. With Bella and Edward, they have 23 and 24 chromosomes. And their baby is perfect.

Um, no. With mismatched chromosomes, you get a deformed (or still born) baby.

Manzanita said...

Very interesting. I haven't thought about chromosomes since the pea pods in high school and that was close to 70 years ago. I don't think DNA was much of a study back then but I always liked genetics.

Robyn Campbell said...

You are a genius, Eagle! And I really mean that. It is a privilege to know ya. *waving*

Anonymous said...

I haven't encountered this info in years. It was great reading this. Biology is my favorite science.

Lynda R Young said...

It's truly astonishing how much we know through science. Looking forward to tomorrow's post.

Rachna Chhabria said...

Very informative post. Interesting info about the X chromosome. Loved the post.

The Golden Eagle said...

Carol: Awesome. :)

Me? I don't know about that one . . .

Thanks! You too.

Moonwyndstudio: LOL. I think I have a bit of that gene myself when it comes to fixing food. :P

Thank you!

Susan: It's nice of you to say so. :)

Science has taken impressive steps in the last century!

Mshatch: The Y post is up now!

I didn't know they were called money cats before. Did you find out the answer?

Jay: Indeed! Their offspring is scientifically impossible. Not to mention a few other things, but that's besides the subject. *ahem*

Manzanita: It's an interesting, constantly-changing field!

Robyn: It's an honor to know you. :)

Medeia: Glad you liked the read!

Lynda: It is.

Rachna: Thank you! :)