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Scientists implant human chromosome in mice

Technology could reveal insights into Down syndrome, other disorders

23 September 2005

LONDON - Scientists have transplanted a nearly entire human chromosome in mice in a medical and technical breakthrough that could reveal new insights into Down syndrome and other disorders.

The genetically engineered mice carry a copy of the human chromosome 21. It is the smallest of the 23 pairs of human chromosomes with about 225 genes.

Children suffering from Down syndrome, which is one of the most common genetic disorders, inherit three copies of the chromosome instead of two.

The achievement caps 13 years of research by scientists at the National Institute for Medical Health in London and the Institute of Neurology.

http://msnbc.msn.com/id/9452451/

Gary - thanks for your post. Related question:
Are the DNA chromosomes in the nucleus - in the
23 pairs - operate as a " read-only " memory
for the cell ?
If they are "read only" and can
be transcribed into RNA, but not altered in-situ, then what does it mean to say " the gene
is expressed" (active) in a particular cell
type and not another cell type ??

What happens when DNA with 23 pairs is
transplanted into an organism that normally
does NOT have 23 pairs ? Does the organism
just use those genes it chooses? Is there any
immune system function that, in effect, says
there is an invalid group of chromosomes in
that particular group of transplanted cells ?

Thanks in advance for your explanation and
response .

I don't do other people's homework. I have never done my children's homework, nor have I ever done my grandchildren's homework. The basic rule is, "Do the assignments yourself." It's not my homework--it's yours. "I've had kids hand in homework that's in other people's handwriting," many teachers have complained. Doing assignments for you won't help you understand and use information. And it won't help you become confident in your own abilities.

Happy learning luckylee

In other words, Luckylee, Garry hasn't got a clue. It's not his field of expertise.

DNA can be read; it doesn't have to be read. As best we can tell, one copy of a chromosome is held as a kind of backup while the other is read and used; its genes are expressed in a given cell.

For a gene to be expressed, it must contain information pertinent to the cell's function. Every cell in your body contains information coding for liver enzymes; only liver cells "express" those genes. DNA is turned on and off according to what tissue type it is in.

As to your third question, only further research can answer that question as you have stated it.

As to our fourth question, the choices of which copy to use are likely made randomly in each tissue and cell type. Dominant genes will be expressed unless they are turned "off" by come cellular mechanism. Hair and eye color are examples of this. Certain colors are dominat while others are recessive. If a single copy of the dominant gene is inherited, it will be expressed. In order for the recessive gene to be expressed you have to have both recesive alleles.

I don't know what you mean by invalid chromosomes. There are proteins that arise with tumors that the immune system can recognize as foreign and attack, but the proteins have to be formed in the cells from RNA using DNA as a template. The seeds of our own destruction are carried within our own cells, in that regard. They may have gotten there by means of viruses. What it takes to stimulate their production is the purview of oncologists.

I hope that helps.

Amaranth, Garry Denke is back to his old tricks. He posts something under his name and then replies under different handles, as he did on the old board with the Stonehenge crap. Don't waste your time getting involved in such a thread, you will only met Gary's multiple personalities.

Whatever

Pasti posted luckylee, lowercase "l" Amaranth

I came here hoping to find something intelligent - you know, intelligent mature people holding interesting debates on issues of science. What do I see? Children and freaks.

quote:
--------------------------------------------------------------------------------
Originally posted by Amaranth Rose:
In other words, luckylee, Garry hasn't got a clue. It's not his field of expertise.
--------------------------------------------------------------------------------

Whatever


WHAT KIND OF RESPONSE IS THAT? AND YOU HAVE CHILDREN - GOD HELP THEM!!!!!!!

Blacknad's first New Topic post:

"GOD AND THE BIG BANG"
http://www.scienceagogo.com/ubb/ultimatebb.php?/topic/1/475.html

This is a Science forum, Blacknad.

Garry,

I know and this is primariy my interest - but on coming here I have seen so much stuff denigrating faith and religion - some of it quite vicious, that I naturally presumed that this forum was fair game for such a post.

Obviously if no one wants to take up the post then that is fair enough.

And my comments were about the amount of insults that were being traded. This just didn't seem to be the place for them.

But having a look at my post, it was a bit harsh...

'Children and Freaks' - I do apologise

Regards,

Blacknad.

Apologise? Surely you jest, Blacknad.

MATTHEW 5:9
Blessed are the Peacemakers: for they shall be called the Children of God.

Peace \/

Garry 'Jesus Freak' Denke
http://www.garrydenke.com

This forum is no different than any other open forum on the net. It is what we - collectively - make of it. If you see behavior you don't like, try not to act like that yourself. It's difficult when other people try so hard to drag you into it, but if you want to keep things the way you like them, then you have to set a high standard for yourself as well.

We live in an age when people praise in themselves what they abhor in others; who demand respect for themselves, but refuse to give it to others; who are eager to take offense and eager to give it; and above all, who covet the right to be obnoxious with impunity.

It's never easy to stay above the fray and you're going to fail from time to time. But if you can keep above it most of the time, and the next guy can do the same and the next and the next and so on, then maybe you can grow the kind of forum in which you would be happy to participate.

Very well said! AS moderator I try to curb the most egregious excesses, but I cannot and will not correct every trangression. I leave it to the forum to adjudicate itself for the most part, and posts like yours are very rewarding to me. Thanks for your participation and wisdom.

"Amaranth"

Well, I was searching the net for science stories and happened upon this sight. I took a look at the forum and was surprised to see so many people insulting each other.

I was also (maybe not so) surprised to find some very harsh attacks on religious people and some insults that I probably haven't heard since I left the school playground. I reacted negatively because I am far from perfect. I regret what I posted and have apologised, which I do again.

Since then I have been reasonable, despite provocation from people who have accused me of burning witches, and worshipping nazis amongst other things.

Regards,

Blacknad.

Blacknad,

Not sure what TheFallibleFiend and Amaranth Rose are on about;
your 'Children and Freaks' I took as a compliment.
Over their heads is all I can figure.

Peace \/

Garry 'Jesus Freak' Denke
http://www.denocoinc.com

My post was not intended as a rebuke for Blacknad. It was my interpretation of the obvious state of the net today. It is what we make of it.

Thank you TheFallibleFiend for sharing your interpretation of the obvious here at our "Scientists implant human chromosome in mice" thread.

U. South Florida researchers study Down Syndrome, Alzheimer's link

October 4, 2005

(U-WIRE) TAMPA, Fla -- Researchers at the Byrd Alzheimer's Institute and the Florida Alzheimer's Disease Research Center, both located at the University of South Florida, are working together to examine the link between Alzheimer's disease and Down syndrome.

The two centers, which work in conjunction with similar centers across the state, are "a consortium of researchers put together to attack the problem of Alzheimer's disease," said Huntington Potter, Eric Pfeiffer chair for Alzheimer's research at USF's College of Medicine. Potter is also the CEO and scientific director of the Byrd Alzheimer's institute.

The link between Alzheimer's and Down syndrome has been established through trisomy 21, the name for the process that occurs when chromosome 21 produces three copies of itself instead of two. Those who have trisomy 21-- Down syndrome patients and some Alzheimer's patients -- have increased production of Abeta1-42, which is the peptide that forms the Alzheimer's plaques on the brain.

http://www.ndss.org/content.cfm?fuseaction=NwsEvt.Article&article=1455