Chromosomes

[El Banana]

Dang, I missed Monarch's post. That sounds about right. Though he switched an X with a Y.

Having no Y chromosome results in death. The human body cannot survive without X chromosomes.

That's an X.

[SS5_Majin_Bebi]

Having no Y chromosome results in death. The human body cannot survive without X chromosomes.

The 23rd chromosome pair is the one that produces Down's Syndrome if you have the wrong number. Gender is (I think) either the 24th or 26th pair.

You are wrong monarch. You can survive without a Y chromosome. Its a female specific condition known as Turners Syndrome. They have only 1 sex chromosome, and its an X. The phenotypic effect is very mild, but they still only have 1 X. and no Y.

but what about this statement?

"The 23rd chromosome pair is the one that produces Down's Syndrome if you have the wrong number. Gender is (I think) either the 24th or 26th pair. "
What what WHAT???

So now humans have 52 chromosomes? I'd go back to the textbooks, there, matey. Humans have 46 chromosomes, thats 26 pairs.

[The Wired Knight]

Um there is no 26th pair. there are 46 chromosomes in 23 pairs. The 23rd is the last one and specifies Gender. Down Syndrome is a triplicate of the long arm of chromosome 21 causing and only one chromosome 14. This is according to www.nas.com/downsyn and my biology and medical text books.

I'll take back what I said about the everybody having the Y thing, that comes from something a bit more complex that I still have some trouble understanding as to the exact coding of that chromosome. There is a small chance that Lyrs won't exibit the actual disease if the SxL gene works properly and "shuts off" one of the X chromosomes and hence makes it innactive (which might be the case from what I understand). what he said about improper meisosis is true, that's where all genetic disorders start. and mutations)

[El Banana]

No dude, you got it wrong. The female GENOTYPE is XX, if you have a Y you are MALE.

[SS5_Majin_Bebi]

I'll take back what I said about the everybody having the Y thing, that comes from something a bit more complex that I still have some trouble understanding as to the exact coding of that chromosome. There is a small chance that Lyrs won't exibit the actual disease if the SxL gene works properly and "shuts off" one of the X chromosomes and hence makes it innactive (which might be the case from what I understand). what he said about improper meisosis is true, that's where all genetic disorders start. and mutations)

Thats true....
Like I said up there *points to earlier in the posts* whether he manifests the symptoms or not depends on what alelles and genes are active. They have to be in a certain configuration. If his SxL gene activates and renders the extra 'X' dormant, he should be fine.

[SS5_Majin_Bebi]

Oh, and I was wrong, there is no such thing as a person with only a Y chromosome. apologies. I think I got it mixed up a little bit with the X0 chromosomal abnormality (Turner Syndrome)

[El Banana]

See, this is where my knowledge gets iffy. As far as I know, the Y chromosome is shorter, and contains less information (which is why you can live with only X's). This is also why males are bald, hemophiliacs, etc. Because these conditions are recessive in the Genes, so females usually have a dominant, "anti-balding" gene in the other X chromosomes. However, since males are missing the information, they have one recessive gene, so it dominates. Which is also why you should blame your MOTHER if you're a balding male (Damn youse, mom!).

I'm gonna be soooo damn bald when I get older...

[jonmartensen]

well...your mothers father.

[El Banana]

Hm... is that so?

Oh yeah, since he's male he could only pass on one X chromosome, the only one he had. So it's the only chromosome that could have the balding coded in it... unless both my deceased grandmother and mother were to turn out to be bald women...

[SS5_Majin_Bebi]

See, this is where my knowledge gets iffy. As far as I know, the Y chromosome is shorter, and contains less information (which is why you can live with only X's). This is also why males are bald, hemophiliacs, etc. Because these conditions are recessive in the Genes, so females usually have a dominant, "anti-balding" gene in the other X chromosomes. However, since males are missing the information, they have one recessive gene, so it dominates. Which is also why you should blame your MOTHER if you're a balding male (Damn youse, mom!).

I'm gonna be soooo damn bald when I get older...

The trick to that is actually quite simple (if you are biologically minded that is)

The reason pattern baldness, haemophilia, colour blindness etc are predominantly a set of disorders mainly in MEN is because we dont have that extra X chromosome that girls do (XX) instead, we have a Y chromosome (Y), its only 'real' purpose to distinguish between male and female. That X chromosome the girls have is a 'fallback' of sorts. All hereditary illnesses are carried on the X chromosome, and they are recessive. Therefore, there are very few colour blind, haemophiliac or balding women. However, if a woman who is carrying the recessive gene marries a man who is afflicted with the same disorder, exactly one half of all the females born will have the disease, and ALL the males born will have it. Its quite easy to work out. Ill do a diagram.

X. X
X.X.X. X.X

Y X.Y X.Y

Where X. is a diseased X (see the little dot i used to denote that), X is healthy and Y is healthy. The Genotype will be X.X. , X.X , X.Y , X.Y that is a Phenotypic ratio of 1:2:1 Meaning One Carrier Female, One Afflicted Female and 2 afflicted Males.

I'm very good at biology and genetics...