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The Gene Is Having an Identity Crisis
gollum123 writes "New large-scale studies of DNA are causing a rethinking of the very nature of genes. A typical gene is no longer conceived of as a single chunk of DNA encoding a single protein. It turns out, for example, that several different proteins may be produced from a single stretch of DNA. Most of the molecules produced from DNA may not even be proteins, but rather RNA. The familiar double helix of DNA no longer has a monopoly on heredity: other molecules clinging to DNA can produce striking differences between two organisms with the same genes — and those molecules can be inherited along with DNA. Scientists have been working on exploring the 98% of the genome not identified as the protein-coding region. One of the biggest of these projects is an effort called the Encyclopedia of DNA Elements, or 'Encode.' And its analysis of only 1% of the genome reveals the genome to be full of genes that are deeply weird, at least by the traditional standard of what a gene is supposed to be and do. The Encode team estimates that the average protein-coding region produces 5.7 different transcripts. Different kinds of cells appear to produce different transcripts from the same gene. And it gets even weirder. Our DNA is studded with millions of proteins and other molecules, which determine which genes can produce transcripts and which cannot. New cells inherit those molecules along with DNA. In other words, heredity can flow through a second channel."
. . . A Human Genome Interpreter Project.
A very simple answer is that RNA degrades *extremely* rapidly. Injecting RNA could feasibly give a short change in phenotype, but it is hard to imagine that RNA would be able to encode something as long-lasting as memory.
You can lead a horse to water, but you can't make it dissolve.
...I'm not (yet) convinced of the value of the gene-mapping you can currently buy. $1000+ and you get back a description that is essentially meaningless because they don't really understand how the genes work yet. You get tested for a handful of conditions which have genetic links, but not all. (Genetic studies have shown there to be 7 forms of ME, according to the specific genetic cause, but very few labs will test for any of them yet.) Without knowing more about how genes work, it is impossible to know if what these studies reveal is even an accurate reflection of the genetics behind such conditions.
Alongside that is an argument in the reverse direction. If genes are not necessarily contiguous and/or can have ill-defined boundaries and/or can have components off the main DNA itself, then there is a definite possibility that there may be additional regions that could be useful for deep ancestry and genealogical DNA testing. This could help enormously as current research is pushing the limits of what is knowable using the regions and markers that are currently available. Entire haplogroup trees have been redefined because new information has revealed flaws in the previous models. More data, preferably more data that changes slowly, could be useful in getting these models right rather than continuously patching them.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
The Force is everywhere, just as Yoda said. The ability for a sentient being to manipulate the Force comes only via midichlorians.
There's your explanation.
And yes, it's still retarded. Best to pretend that never happened.
The enemies of Democracy are
Think of it this way- if your protein-coding genes are the blueprints for a car, then epigenetics are the blueprints, operating procedures, and logistics for a mass production automobile factory. By reading your genes, you can find out the kinds of proteins that make you up. Similarly, car blueprints tell you how to make a car. A car, just one car. However, your cells are not putting out handbuilt cars. It's a modern Toyota factory going on in there, with continuous production and assembly. It's a marvel of mass production, with transcription, splicing, translation, post-translational modification, and relocation to the site of use all going on in multiple sites constantly. Production has to be carefully coordinated to make sure you have the right amounts of the right proteins delivered at the right times.
Epigenetics is the guy at the factory who knows how many cars to build this month, and the guy who makes sure that 10,000 cars have 10,000 steering wheels available to put in. Epigenetics is the guy who tells the line to hold up on building doors, because there's a surplus of doors in the warehouse already and we should use those first. Epigenetics is not the stuff you are made of, but rather a system of production control of that stuff.
"FDA staff reviewers expressed concern about the number of patients who were left out of the study because they died."
Sorry, not true. There ARE mechanisms for creating new RNA not encoded in the DNA. Enzymes can shuffle around RNA sequence (as in RNA splicing), or change single nucleotides. Interestingly, the base changes occur most often in the nervous system of mammals. However, as mentioned, RNA doesn't stick around long enough to be responsible for memory. http://en.wikipedia.org/wiki/Rna_editing
Can you define instinct so we can talk intelligently about it?
GPL Deconstructed
Computer memory is actually a pretty good analogy for this: the "unused" DNA is not reachable by any "pointers" and thus wasn't important when eucaryote evolution began. Some of these areas are obviously non-coding ever-repeating nonsense sequences, others appear to be random information - exactly like unused RAM in a computer system. Of course, nothing in there is really random, it's just a product of whatever process happened to use the areas before.
Here's the catch, however. Just like a programmer who develops against an ancient API with a lot of well-known bugs and workarounds, some transcription mechanisms actually began to rely on the presence of the "useless" areas in order to work.
It's all a huge mess, the deeper you look, the less elegant it all becomes. For example, epigenetic mechanisms modify the meaning of DNA code depending on different contexts, as the article mentioned. But that's still not the whole picture. In order to create a protein, DNA is first transcribed into RNA, which then in turn gets executed in order to assemble the protein. However, the intermediate RNA information is modified beyond recognition before it is used. Then, after the protein is finally assembled, it too can be modified extensively. All of these steps are hopelessly interwoven, and they use zillions of chemical messenger signals in order to tweak an manipulate each other.
Genetics really is the worst spaghetti code project ever and I assume that more advanced (=complex) organisms really paint themselves into an evolutionary corner eventually, because the whole system - while beautifully specialized - is essentially becoming more and more difficult to alter meaningfully when radical change needs to happen.
That's biology for you - everything that can happen does happen and every seemingly elegant mechanism turns out to be an incomplete story. Life on earth is a total mess and badly overdue for extensive refactoring :)