Even less genes in the human genome!

[betazed]

Well, I will continue XIII's work and post this bit of science news...

link

scientists have found that the number of genes in the human genome are now even less than their earlier estimate. now it is close to 20,000. Earlier it was thought to be around 30,000. This is a far cry from the initial hundreds of thousands of genes everyone thought the human genome will have.

I wonder if the number of proteins in the human body will be far more than 20,000 or not?

 

[stormbind]

Don't see how. Number of proteins is surely less than the number of genes.

It's just like a jigsaw puzzle. Have you ever noticed how the anticpated required table space shrinks as it nears completion?

 

[betazed]

Don't see how. Number of proteins is surely less than the number of genes.

Nope. Number of proteins can be far more than the number of genes. The pre-mRNAs created from the same gene can be spliced to create different mRNAs which create different proteins. I know that happens in some cases. Maybe that is happening more than we think.

It's just like a jigsaw puzzle. Have you ever noticed how the anticpated required table space shrinks as it nears completion?

Or maybe evolution is far more precise and less random than we thought.

 

[Tassadar]

I think that we are far aways from understanding evrything invovle in molecular information storage. What they call junk DNA may indeed show tremendous use under unexpected circonstance.

I will add this study that seem to contradict myself, but let me emphasis the final quote,

"Survival in the laboratory for a generation or two is not the same as successful competition in the wild for millions of years," he argues. "Darwinian selection is a tougher test."



Recent article about junk dna in mice:http://www.nature.com/news/2004/041018/full/041018-7.html

The working of our mind is store into that molecule, modern physic cant even explain our mind,exept by using hypothetical quantum theory, right?

 

[Pirate]

Wow, so that means that even more of our genome is 'junk' DNA.

I find that interesting because an article in a recent Scientific American is all about how this is not just junk. The amount of protien coding genes is seemingly not directly related to the complexity of an organism. Some worms have as many protien coding genes as we do, some amoebas actually have more! But the non-coding 'junk' DNA is directly proportional to the complexity of a multicellular organisms. The article mentions how these introns code for RNA which may help guide protiens and RNA to the correct spots in cells and act as a feedback mechanism to say "ok this reaction has taken place, now we go here". (There's more to it but it's tough to summarize)

Betazed's article seems to support this idea that protiens are important, but seemingly not as important as we thought. If we only study these 20,000 genes then we are looking in the wrong place.

http://www.sciam.com/article.cfm?chanID=sa006&colID=1&articleID=00045BB6-5D49-1150-902F83414B7F4945
<edit - oops, that's not the whole article. You have to pay for the full thing. Sorry. I'll try to summarize later if it is relevant>

<edit again - Tassadar's article seems to contradict mine. Will read more....>

 

[Knight-Dragon]

Well, I will continue XIII's work and post this bit of science news...

Carry on...

I've come across a news bit that the no of human genes is less than some plant.

 

[betazed]

@Tassadar: Thanks, for that link. I was wondering when someone would do that particular experiment and post the results. Next, I would like to see how a mice performs after we have removed 90% of its introns instead of just 3%.

The article mentions how these introns code for RNA which may help guide protiens and RNA to the correct spots in cells and act as a feedback mechanism to say "ok this reaction has taken place, now we go here".

I am a bit confused here. Last I knew, Introns do not code for anything. Actual genes code for both RNA and proteins. So we have protein coding genes (i.e genes which are used to code proteins finally) and RNA coding genes (genes whose final result are just RNA and not proteins). However, as i said earlier introns do serve two distinct known purposes

(a) they allow the same gene to create more than one protein
(b) they allow gene recombination to create genetic variability.

 

[Aphex_Twin]

Or perhaps there is no clear definition of what a gene is. If a gene is a fragment of DNA code that gives one characteristic of the said life form, there deffinately is room for interpretation.

 

[Tassadar]

Next, I would like to see how a mice performs after we have removed 90% of its introns instead of just 3%.

Performs in a lab environement, or performs many generations in different natural environements ?

 

[Perfection]

@Betazed, introns are part of genes which after being transcribed are snipped and thus prevented from coding.

I wonder if they are refering to genes only as protien coding ones or ones that create just RNA as well

 

[betazed]

@Betazed, introns are part of genes which after being transcribed are snipped and thus prevented from coding.

I know. why did you think I meant anything else?

I wonder if they are refering to genes only as protien coding ones or ones that create just RNA as well

They meant protein coding genes.

reducing the estimated number of human protein-coding genes from 35,000 to only 20,000-25,000, a surprisingly low number for our species

 

[Tassadar]

Genes need to be define, we are taking the molecular biology sens here, but there is a little more.

A good global multidisciplinary definition:http://www.wordiq.com/definition/Gene


Edit, chemical definition of DNA ( merk index, my old chemical bible);

DNA is beleive to be the genetic carrier information. In this role it must have 2 function: be exactly reproductiblein order to transmit its genetics information to futur generations; contain information, in chemical code, to direct the devlopementof the cell according to its inheritance.

DNA also acts as a template in the formation of ribonucleic acids; the latter play a fundamental role in the synthesis of proteins in the cell.

There is alots of other technical information that i will spare you.

 

[Tassadar]

Carry on...

I've come across a news bit that the no of human genes is less than some plant.

Quote,

About 97% of the human genome has been designated as "junk". The onion genome is 12 times the size of the human one, presumably because it contains even more junk. In contrast, the pufferfish genome is only about one tenth the size of the human, yet seems to have about the same number of genes. Therefore it seems that the ratio of functional and junk DNA differs widely per species.

Junk DNA definition link:http://www.wordiq.com/definition/Junk_DNA

 

[Tassadar]

Ok, after some and i am no more shy to elucubration, so let go.


IMO protein are the life nanobuilder, those little builder are able to store information as DNA and they use a printed press call RNA.

What is driving those nanobuilder rely probably in some undiscovered neo-quantum theory.

But the fact is , they built lifeform and store their information, for self replication and further macroscopic newtonian adaptation to natural environement. So there is a link between the micro world ( chemical bio-feed back) and the macro world ( our reality).

By cuting ''junk DNA'' , it is like removing the page from the architect book. He may still be able to built the bank, but unable to built the police station to defend it. ( think about our adaptative auto-immune system).

Why the cosmic energy which have crystalise into matter through star's nucleosynthesis and assemble living form from their dust, will carry chemical ''junk information'' about adaptative self cousciousness life?

 

[Perfection]

I know. why did you think I meant anything else?

They meant protein coding genes.

You're still not getting it, introns are just the non-coding sections of protien coding genes not the vast expanse of "junk DNA"

 

[Pirate]

Introns are transcribed along with the protien coding portions, then the gene coding DNA is spliced out and reassembled as messenger RNA. According to the article I quoted, some of the remaining introns are processed into microRNA and communicate regulatory information by "tagging or grabbing particluar sequences in primary gene transcripts and steering how the spliceosome joins the pieces" (Quote from Scientific American, Oct.04)

 

[betazed]

@Perfection: You are correct. I was using the definition non-coding dna (which would include introns) = junk dna which is obviously incorrect. The correct definition would be non-coding dna for which no other function has been identified (which thus excludes introns) = junk dna.

I will correct my previous post.

 

[Tassadar]

Another study about trisomi 21 show how the genetic issue is much more complex then taugh, i like this quote,

"The very simplistic explanation we had before was wrong," says Roger Reeves, from the Johns Hopkins University School of Medicine, Baltimore, who is one of the study's co-authors.


Link:http://www.nature.com/news/2004/041018/full/041018-14.html

 

[Renata]

@Tassadar: Thanks, for that link. I was wondering when someone would do that particular experiment and post the results. Next, I would like to see how a mice performs after we have removed 90% of its introns instead of just 3%.



I am a bit confused here. Last I knew, Introns do not code for anything. Actual genes code for both RNA and proteins. So we have protein coding genes (i.e genes which are used to code proteins finally) and RNA coding genes (genes whose final result are just RNA and not proteins). However, as i said earlier introns do serve two distinct known purposes

(a) they allow the same gene to create more than one protein
(b) they allow gene recombination to create genetic variability.

I'm also wondering about the claimed relationship between percentage of junk DNA and complexity of the organism. Are you 100% sure of your source, Tassadar? I could've sworn I read once somewhere that the fugu fish has very little non-coding DNA, and that's a pretty complex organism.

Yeah, here's a cite: article

First article in a Yahoo search on "fugu fish intron". First sentence of the abstract:

The puffer fish Fugu rubripes (Fugu) has a compact genome approximately one-seventh the size of man, mainly owing to small intron size and the presence of few dispersed repetitive DNA elements, which greatly facilitates the study of its genes at the genomic level.

So I think you're probably off base here.

Renata

 

[Tassadar]

But my source say exactly the same, no? quote,

the pufferfish genome is only about one tenth the size of the human, yet seems to have about the same number of genes.

So it mean it have very low ''junk information'' or little non-coding DNA, right?


But personaly i dont like the geneticien view, i will never call chemical infomation related to lifeform, ''junk information''. There is too much unknow.