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New Class of Genes Discovered
HarryGenes writes "Reuters is reporting that Scientists Find New Type of Gene in Junk DNA. The research from Harvard Medical School describes a discovery in the Yeast Genome of a new class of gene that regulates the neighboring gene through the production of its RNA product. This has much broader implications than the article lets on to. Assuming these same type of genes exist in Humans and other organisms, the whole science behind gene expression and gene mapping will be changed dramatically. This type of mechanism can explain a lot of the 'unexplainable'. This is really exciting. I have been working in gene mapping for years and always felt that the 'junk' was there for a reason."
Much more information can be found in this article taken from pubmed.
Stealth regulation: biological circuits with small RNA switches
If you visit the story at The Scientist, they have a much better article and a link to the PubMed, full text article.
New Scientist has an article about some scientists who removed pretty huge chunks of a mouse's "junk DNA" and the mouse was just fine in every way they could measure.
So the moral is, we have a lot to learn about DNA.
Man, I don't know. Animals are one thing, but plants are quite another. Ever check out plant genetics?
I'm more of an animal guy, but my ex was into plant biology, and her take on the whole plant genetics thing is nothing less than... very worrisome. Plants swap and adopt chromosomes, hybridize, etc. much more freely than animals.
The problem therefore is not that the actions of a gene in one species aren't known (though I'm not convinced they're know well enough); it's that the gene can get into other species far too easily. There are bigger nightmares in that scenario than a few allergic reactions.
I'll be the first to admit I'm no expert in plant genetics - but a fair number of people who ARE experts are concerned. I'm inclined toward caution. I'd suggest that the best thing to do is to clearly label products containing material from GMOs and let the consumers decide, but the shee^H^H^H^Hconsumers are the same folks with unpatched Windoze boxen. Cheers!
Corruptissima re publica plurimae leges.
Sorry, but they already are!
A single gene can contain up to three overlapping reading frames, and some virii and bacteria can generate three completely different and functional proteins from the same gene sequence by this method. Add to that that certain gene products may be broken into subunits at different points along their sequence, and a highly-evolved (or carefully designed) gene could encode >10 proteins.
Interestingly, the mechanism was actually understood before functional miRNAs had been discovered. Back in the 90s there was an upswelling of new biotech companies (Isis, for one) looking at antisense technology. Basically, the idea is that if you insert a complementary RNA strand to a messenger RNA (mRNA- The RNA's which code for proteins), you could block the expression of that gene into protein. The problem was that these weren't very specific (relative to what people would expect, since it was the exact complement of the gene sequence). Also, it's a bitch to get a full length RNA strand into cells reliably, short of using viruses. Generally a bad stigma.
Over time, people started realizing that these antisense targets being inserted were being cleaved into really small (~20 to 25 nucleotide) pieces by an enzyme group called the RISC complex (It's a lot more complecated than that, but whatever). This explained one thing. ~20 nucleotide chunks are much more likely to stick to another gene. There's a much better chance that the 20 bases are identical to 20 bases in another gene, than several hundred to several thousand being repeated. What it didn't answer is what was going on.
It was assumed that the complex that large antisense targets made blocked translation into protein. 20 base pieces were much less likely to do that. What people came to realize is that another enzyme called DICER was chomping up the genes where these ~20 nucleotide pieces stuck. This technique isa called RNA interference, or RNAi, and these ~20 nucleotide sequences were called short interfering RNAs or siRNAs. The sweet thing is these, relative to their much longer antisense couterparts are relatively trivial to insert into cells.
Anyway, to make a long story short, researchers didn't really know why this worked at first, and consensus was that it was either an evolutionary legacy, a mechanism to fight RNA viruses, or a fluke (which generally, very few things in biology end up being).
Anyway, this article points out what researchers all over are finding which is that these little guys appear to be present all over the human and other genomes. They are much more likely to be a mechanism for regulating gene expression. For more info, google 'micro RNA'.
Cheers