alternative splicing as a way to create more genetic information

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spuriousmonkey

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Prof. Spuriousmonkey: As we might know the human genome contains about 30-35.000 genes. Drosophila doesn't have much less with an estimated 30.000.

Pupil: So it takes 30.000 genes to build a complex organism then Prof. Spuriousmonkey???

Prof. Spuriousmonkey: Yes, but that is not the whole story. Most genes can be spliced in different ways.

Pupil: But Prof. Spuriousmonkey what is splicing? Does that have anything to do with nuclear bombs and Saddam hoessein?

Prof. Spuriousmonkey: Haha, very funny my dear pupil. No my dear child, a gene is encoded on DNA. Somehow this information has to be processed into a different form. We want to build proteins for instance! Well, the DNA is translated into RNA. The RNAs that encode proteins are called Messenger RNAs, in short mRNA.

Pupil: why not write messenger fully. I like the word.

Prof. Spuriousmonkey: That is because scientists are lazy and do not want to exert themselves too much when they are typing their latest groundbraking paper.

Pupil: aha. So that is it? We have a mRNA and that is translated into a protein?

Prof. Spuriousmonkey: What we have is an unprocessed messenger. In the eukaryotic cell this messenger undergoes many forms of processing, one of which is splicing.

Pupil: SPLICING of MESSENGERS!!! NOT ATOMS!!! I SEE…

Prof. Spuriousmonkey: Calm down lad. We are not in an amusement park here. This is a science class.

Pupil: Sorry…please go on Professor.

Prof. Spuriousmonkey: This mRNA contains so called exons and introns alternating each other. The exons actually encode the protein, but the sequence is broken up by introns, which do not encode the protein.

Pupil: That's silly.

Prof. Spuriousmonkey: No, that is nature. It is actually quite an interesting concept.

Pupil: Why?

Prof. Spuriousmonkey: Because the exons have to be joined up. This process is called slicing. They slice away the introns as it were.

Pupil: But why make things so difficult?

Prof. Spuriousmonkey: Because a mRNA doesn't always have to be spliced up with the same exons. Sometimes they have some extra exons, sometimes they leave out other exons. You can create by this process entirely different mRNAs, although it is only one gene.

Pupil: A single gene can make different proteins altogether!!!

Prof. Spuriousmonkey: Indeed, and moreover some genes are know to contain more than 200 exons and introns. And for instance the DSCAM drosophila gene theoretically has over 38.016 splice variants. This alternative splicing therefore could be another way to create more genetic information besides increasing the number of genes.
 
maybe someone would like to discuss splicing...it's after all a biological topic, instead of the more common pseudoscientific topics.
 
Would you like to suggest a more specific topic regarding splicing that people can discuss?
 
Then why bring it up at all?

However, if anyone wants to delve into the topic, then I would be more than interested in discussing it. I wasn't directing my earlier comment to you specifically.
 
Originally posted by Idle Mind
Then why bring it up at all?

However, if anyone wants to delve into the topic, then I would be more than interested in discussing it. I wasn't directing my earlier comment to you specifically.
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i brought several points worthy of discussion up in the first post...i'm not going to spit things out for other people. If they see something interesting they can continue to discuss it.

I will make an exception here and highlight some possible topics:

Originally posted by spuriousmonkey
Prof. Spuriousmonkey: As we might know the human genome contains about 30-35.000 genes. Drosophila doesn't have much less with an estimated 30.000.
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isn't it strange that the supposedly enormously complex human doesn't have much more genes than a humble fruitfly? Does this mean we are not as complex as we think we are?

Originally posted by spuriousmonkey
Pupil: So it takes 30.000 genes to build a complex organism then Prof. Spuriousmonkey???
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how is it that we can make a complex organism with only 30.000 genes. Could we do it with less?
Originally posted by spuriousmonkey
Prof. Spuriousmonkey: What we have is an unprocessed messenger. In the eukaryotic cell this messenger undergoes many forms of processing, one of which is splicing.
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Originally posted by spuriousmonkey
what other mechanisms of mRNA processing are there?
Prof. Spuriousmonkey: This mRNA contains so called exons and introns alternating each other. The exons actually encode the protein, but the sequence is broken up by introns, which do not encode the protein.
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why and how did the exon and intron system evolve?
Originally posted by spuriousmonkey
Prof. Spuriousmonkey: Indeed, and moreover some genes are know to contain more than 200 exons and introns. And for instance the DSCAM drosophila gene theoretically has over 38.016 splice variants. This alternative splicing therefore could be another way to create more genetic information besides increasing the number of genes.
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Are all splice forms used in nature and do they have different functions.


And I didn't even try hard to raise questions…

It is not me that doesn't see potential in this topic. It is the reader. I am merely testing the inquisitiveness of our fellow posters. It is all a big experiment to me.
 
spuriousmonkey continues s/he conversation with the wall, spuriousmonkey seem to be enlightened by this conversation, the wall on the other hand is looking bored.

Ok aaah lets not stare at s/he, try to ignore this and someone call the asylum.
 
I would have to consult Fragglerocker, but I think that writing for someone else might be interesting, but writing for yourself is best.
 
Originally posted by spuriousmonkey

isn't it strange that the supposedly enormously complex human doesn't have much more genes than a humble fruitfly? Does this mean we are not as complex as we think we are?
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Just because we are bigger and smarter doesn't mean we have alot more proteins and cell types/organ types then the fruitfly does. If you look at a fruit fly magnafied to human sized it would look pretty complex. 17% more genetic material should be plenty to account for our "extra features". The fruitfly has a bunch of unecesary genetic material, then again we have some unecesary genetic material aswell.
Originally posted by spuriousmonkey

how is it that we can make a complex organism with only 30.000 genes. Could we do it with less?
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Considering how evolution works, if someone were to 'handcode' a human or fruitfly it would no doubt have a smaller number of genes. But gene repetition is good for cancer and mutation prevention.

Originally posted by spuriousmonkey

why and how did the exon and intron system evolve?
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No idea really. Unless you want something uninspired like 'it worked'.

I don't have time atm to really go through this, and raise some more 'interesting' questions as you put it, but I'll be back.
 
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