Deletion of Junk DNA has no ill effects

Re: Deletion of Junk DNA has no ill effects

Badboy wrote:

Scientists have found deleting junk DNA from a mouse genome had no ill effects.

Could one do without junk DNA?

An individual could probably do without its own junk DNA, but it was my understanding that the "junk" DNA is only junk because it's not active (producing proteins) in the individual, and that this could change due to mutation from generation to generation.

I think the Junk DNA is a pool of genetic resource which had some function in our ancestors, but which is inactive now. I think the "junk" benefits evolution of the species (by providing mutation more raw material to work with), even if not the individual.

One generation's junk is another generation's treasure.

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Any programmer will tell you, these sequences aren't "junk". They are comments.

Removing them won't officially make any functional difference, but it will make the organism much harder to maintain.

Removing the comments left in the DNA by the original deisigner is plain bad engineering practice.

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ebrown_p wrote:

Removing the comments left in the DNA by the original deisigner is plain bad engineering practice.

What designer?

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I don't know, I haven't looked at the DNA code.

I usually put my name in a comment at the top of the work that I do.

Has anyone checked the Human DNA for "Author" field. I would think it would be in one of the first comments.

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Hmmm I think that so called "Junk DNA"s are just the ones that is hidden...... or potential DNAs, if you know what I mean. They may, or can be triggered off to function by something. Although the question is what. Wink

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Re: Deletion of Junk DNA has no ill effects

rosborne979 wrote:

An individual could probably do without its own junk DNA, but it was my understanding that the "junk" DNA is only junk because it's not active (producing proteins) in the individual, and that this could change due to mutation from generation to generation.

I think the Junk DNA is a pool of genetic resource which had some function in our ancestors, but which is inactive now. I think the "junk" benefits evolution of the species (by providing mutation more raw material to work with), even if not the individual.

One generation's junk is another generation's treasure.

On the other hand, it might simply be that much of the "junk DNA" doesn't code for anything, but arises purely out of chance mutations and errors in replication. If the replication errors do not create a substantial cost to the organism, then they will not be selected against. Not everything is adaptive or maladaptive. It therefore wouldn't shock me if some of this DNA was totally useless.

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Re: Deletion of Junk DNA has no ill effects

Steppenwolf wrote:

It therefore wouldn't shock me if some of this DNA was totally useless.

I'm sure some of it is. I just don't know how much. I'm guessing that out of the 90% which appears to be total junk, only 20% actually is junk.

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Re: Deletion of Junk DNA has no ill effects

rosborne979 wrote:

I'm sure some of it is. I just don't know how much. I'm guessing that out of the 90% which appears to be total junk, only 20% actually is junk.

Perhaps. It's simply too early to tell. However, in some organisms with enormous amounts of genetic material, like some amoebas and onions, much of the alleged "junk" DNA is probably actual junk.

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Junk DNA does provide an excellent harmless target for any transposable elements that might be creeping around in our genome, though. Take away all the junk DNA, then sources of non-random insertional mutations (from transposons, retroviruses, whatever) will only be able to go after sequences we actually need.

I'm not sure how frequently this stuff actually occurs in animals, but the footprints of past activity are there -- indeed, they comprise a pretty considerable portion of so-called "junk" DNA.

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Due to the typically gross wasteful nature of any biological system, it is hardly remarkable that a goodly percentage of the DNA, and RNA hanging around as 'excess baggage' in our genetic storage lockers is useless junk.

Biology is nothing, if not wasteful, and rarely is anything discarded, unless it be the entire animal.

Seeking out the 'junk', and discarding it might make for a magnificently 'minimal' cell structure, but it would be not worth the effort, and risk involved, and the 'chaff' would probably build up again the next time you launder your 'genes'!

Shocked

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Recently, I read an article which said that while the DNA of Humans and Chimps is almost identical, the proteins being produced to build the organisms are very different (in proportion). I think the article was suggesting that the differing results of the DNA indicate that there is more to the functionality of DNA than simply its component pieces. The order and location of the genes in the strand seem to contribute greatly to the protein production, perhaps more so than simply the availability of the genes themselves.

I don't have a link to the article, but I'll see if I can find it.

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Timber posted a very good article about this issue in another thread.

Click Here To See.

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Actually, scienticts think that introns (the 'junk' DNA) are in fact very crucial for an eukaryotic organism. A gene is transcribed into RNA, which then moves out of the nucleus to the ribosomes that reside either in the cytoplasm or on the rough endoplasmatic reticulum (RER). The ribosomes are able to translate the mRNA and make proteins out of it. The introns, however, are separated from the exons (the parts of the RNA that exit the nucleus and are transcribed) before the RNA leaves the nucleus.

The RNA introns thus stay in the nucleus. This separation of small parts of RNA enables the cell's genome to shuffle its exons; after slicing the RNA and taking out the introns, the exons can be put together in a different order. This is also called alternative splicing, and it basically enables the cell to produce different proteins out of one gene, which is in agreement with what is called the parsimony of life.

The introns are also believed to be useful for something else; about 20 years ago, scientists discovered that RNA can have a similar function to enzymes. These RNA parts are called ribozymes, and ribozymes are thought to have different functions. The actual splicing of the introns is actually believed to be done by a spliceosome, which consists out of snRNA (small nuclear RNA) and many protein molecules. The snRNA is what catalyzes the splicing, however. The proteins have no catalystic function in it.

Go here for more information on ribozymes.

Not all 'junk' DNA is junk. It is essential for an eukaryotic organism; it is believed that junk DNA is what makes us so different from other species.

'Junk' DNA was just an unfortunate choice of words... because it is not junk at all.

Stefanie

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Adrian wrote:

Timber posted a very good article about this issue in another thread.

Click Here To See.

Thanks Adrian, this is an interesting article, but it's not exactly the one I was thinking of. The one I remember was mainly talking about Protein production. It might have been on CNN or UPI.

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Is "Junk DNA" just an excuse for the ignorance of Geneticists?

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Depends...

Would you call the Mendelian approach to genetics "ignorant" in light of the modern understanding of genetics?

Science (unlike religion) does not pretend understand the Universe perfectly.

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Oh, yeah? Well I deleted some of my junk DNA this morning, and I feel sick as a dog.

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Quote:

Recently, I read an article which said that while the DNA of Humans and Chimps is almost identical, the proteins being produced to build the organisms are very different (in proportion). I think the article was suggesting that the differing results of the DNA indicate that there is more to the functionality of DNA than simply its component pieces. The order and location of the genes in the strand seem to contribute greatly to the protein production, perhaps more so than simply the availability of the genes themselves.

If you mean very different protein expression -- the notion that humankind is a neotenous form of ape (one in which a phenotypically immature form reaches sexual maturity) might help account for this. Change one regulator and you can change the actions of dozens of genes.

An interesting example of such an animal is a salamander called the axolotl (http://www.encyclopedia.com/html/a1/axolotl.asp), which in iodine-deficient conditions reaches sexual maturity without ever undergoing metamorphosis. There is apparently a host of anatomical data tying human evolution to neoteny -- thus allowing for a huge phenotypic change with minimal changes in the DNA.

If you mean very different protein structures -- a single nucleotide substitution in a gene (say, one in 600) can result in an amino acid substitution in a protein (say, one in 200). Percentage differences in genetic material do not translate directly to percentage differences in protein sequences.

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DrewDad wrote:

Depends...

Would you call the Mendelian approach to genetics "ignorant" in light of the modern understanding of genetics?

Science (unlike religion) does not pretend understand the Universe perfectly.

Then why use the word "Junk" ?

There are various "scientists" who do pretend, though, unfortunately.

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Deletion of Junk DNA has no ill effects

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