Slashdot Mirror
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."
One experiment that was purported to show a chemical basis for memory involved training planaria to solve an extremely simple "maze", then grinding them up and feeding them to untrained planaria to see if they would be able to learn more quickly. The experiment seemed to show such an effect, but it was later determined that the original planaria had left chemical tracks inside the maze itself that were not properly cleaned away before the next set of planaria were run.
It's not a complete explanation, but it implies that pathfinding behavior(e.g. getting out of a maze) had much more to do with following a chemical "bread crumb" trail than using memory alone.
Epigenetics
RNA Splincing
siRNA
RNA is a copy of DNA created by an enzyme called RNA Polymerase. All RNA Polymerase does is a simple copy. There is no mechanism for creating "new" RNA that contains data that is not already present in your genes. That is, your body does not contain any device that can write memory information to RNA strands.
You forgot the link
It has been known for a long time that junk DNA wasn't junk. However its one of those catchy memes that has persisted it the general public far longer then it was believed to be true.
Control is an illusion, order our comforting lie. From chaos, through chaos, into chaos we fly
The term 'gene' has undergone quite a bit of change in its history, so this isn't really all that surprising in light of this. The term was originally coined (probably by Mendel himself, but I don't remember) to mean roughly "whatever is responsible for the observable results of hybridization experiments" and later, with the advent of molecular biology, came to be shorthand for referring to a molecular structure of a certain kind. It's an interesting question of course, whether those definitions are coextensive (my bet is they aren't) and these latest findings are just evidence of a new conceptual (or at least terminological) shift. See Stotz and Griffiths "Gene" (2005) (to appear in Cambridge companion to philosophy of biology, and also can be viewed online at http://philsci-archive.pitt.edu/archive/00002494/ )
None of what was mentioned in the article is even new to biologists, or at least geneticists. This stuff is taught in a general genetics course, suggesting that this has been accepted for years prior.
"Junk DNA" probably hasn't been stated in any serious, meaningful way by genetics in decades, and probably was never meant to be taken seriously--especially since research in gene expression took off. Not to say that there aren't any junk DNA, there certainly are, but the media took something interesting and blew it out of proportion like they always do. The real clue was how some supposedly junk DNA was very conserved, and the fact that you'd think that a genome full of junk would eventually get smaller and smaller with time considering the amount of energy it takes to replicate and package such a load. To think that geneticists simply thought it was all useless junk flies in the face of logic.
Yep. And there are other kinds of non-chromosomal bodies which transmit genetic information, too — see the Wikipedia article on Extranuclear inheritance, to start with. And this has been known for a very long time; the book I just used to check my recollection of this was copyrighted in 1970!
I've read the Bible cover to cover. That's actually pretty much WHY I'm an atheist. Have you read that it? It's retarded. Seriously. It was obviously written by a bunch of primitive hicks millenia ago. It's just superstition.
What was the question again?
"What do you get when you multiply 9 times 5."
The higher the technology, the sharper that two-edged sword.
One experiment that was purported to show a chemical basis for memory involved training planaria to solve an extremely simple "maze", then grinding them up and feeding them to untrained planaria to see if they would be able to learn more quickly.
This reminds me of VG Cats.
So wrong..
How many genes must a geneticist wear out before we call it a gene?
The answer my friend,
is bubbling in a lab.
The answer is bubbling in a lab.
how is babby formed?
Also Lamarckian style, or at least very flexible in the short term inheritance
http://www.nature.com/ejhg/journal/v14/n2/full/5201567a.html
http://en.wikipedia.org/wiki/Epigenetics
There was Frontline and a Nova on this like 2 years ago.