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New Genes May Arise From Junk DNA
An anonymous reader writes: Junk DNA (or noncoding DNA) is a term for section of a DNA strand that doesn't actually do much. Huge tracts of the human genome consist of junk DNA, and researchers are now finding that it may be more useful than previously thought. "For most of the last 40 years, scientists thought that [gene duplication] was the primary way new genes were born — they simply arose from copies of existing genes. The old version went on doing its job, and the new copy became free to evolve novel functions. Certain genes, however, seem to defy that origin story. They have no known relatives, and they bear no resemblance to any other gene. ... But in the past few years, a once-heretical explanation has quickly gained momentum — that many of these orphans arose out of so-called junk DNA."
One of the properties of junk DNA is that it can endure brutal mutations since it's not used for anything. So over time it can change a LOT. Then suddenly another mutation suddenly activates it by mistake and *poof* you have a new magic super-power (more often than not, lethal). Starting from a crucial gene won't work since the slightest modification will reduce your survival rate, since by definition it's crucial.
Non-Linux Penguins ?
I suspect that in the future, scientists will laugh at the notion of "junk DNA" and think of it as just as much of a myth as "you only use 10% of your brain".
What is heretical about novel new genes arising out of junk DNA? Molecular biologists have known for many years that so-called "junk" DNA played a number of roles; regulatory, and that most certainly novel genes could arise.
Oh, I get it, this is the idiotss otherwise known as "scientific journalists" hyping up a rather unremarkable finding, and fixating on the word "junk" much as they, in ignorance and the need to sex up stories, concentrated on the word "God" in the "God particle"
The world's burning. Moped Jesus spotted on I50. Details at 11.
That's always been the key to genetic evolution. This is somehow new??
So basically there's a bunch of spare stuff laying about which, under the right circumstances, can actually change into something new and unexpected.
This is good, because it means we have more potential than what we already have. It also explains why organisms aren't constrained by things which came before them.
I still get the impression we still don't understand how all this works. Which is good. Because people start thinking science has answered everything, only to find out there's tons more to go.
Lost at C:>. Found at C.
It's short hand. Scientists haven't thought of it literally as junk in many years. It's like "black hole" and "god particle", funny little shorthand references that don't necessarily reflect what researchers think at all.
The world's burning. Moped Jesus spotted on I50. Details at 11.
So take your pick, is Einstein wrong
Science proceeds toward understanding of nature that is less wrong* over time. So it's very probable that Einstein didn't have the whole story.
Aristotle was wrong about the relationship between mass and acceleration due to gravity. Galileo Galilei proved him wrong. Galileo was wrong about gravity being independent of location. Isaac Newton proved him wrong. Newton was wrong about the effect of gravity at what we now call relativistic speeds. Albert Einstein proved him wrong. Einstein was still wrong about "God doesn't play dice with the world." Each of them stood on giants' shoulders to become less wrong.
* Yes, "less wrong" is a thing. Assuming that "wrong" is an ungradable adjective like "unique", "perfect", and "parallel" is a fallacy.
Likewise, NEWTON WAS NOT WRONG! That was the foundation for more than 200 years, from 1687 to 1915.
... is that hybridization might play a very big role in the appearance of new species, in several different ways:
- apomixis, producing some (most often aneuploid) news organism (which then clones itself indefinitely by fragmentation, budding or parthenogeny, becoming a distinct species all by itself)
- polyploidization, where the different DNA sets just add up and coexist side by side (like in pretty much every angiosperm on the planet, and many other plants, as well as many fish, reptile and salamander species - like Ambystoma platineum)
- symbiotic association, as seen in lichens and also in how mitochondria fused with bacteria into eukaryotes
- recombinational stabilization (a.k.a allohomoploid nothospeciation), where the slightly mismatched chromosomes from different DNA sets of compatible but different species pair up into complex heteroduplexes that end up fragmenting or fusing chromosome segments when the first generation of hybrids starts mating - which very well might be how two chimpanzee's chromosomes fused into our own bigger Chromosome 2.
In the cases mentioned of TFA some of the 'exotic' genes may be explained more simply as introgressions from a past hybridization event with a different species followed by backcrossing.
Maybe we deserve this world ?
so I'm not carrying all this stuff for nothing. I'm so glad to be a member of a species that thought otherwise for so long. I like my appendix too, by the way, also the other 80% of my brain, thanks very much.
Its just poorly understood DNA sections. The ENCODE project studied non-coding DNA and estimated that up 80% could be important. Some codes for RNA which until recently was hard to measure because it decays so rapidly. Some may encode for epigentic control like methlyation locations. Some may control the folding of histone-DNA complexs, forcing sections sections DNA to be nearly one another for reasons we dont understand yet.
Clever biochemists will figure these out soon enough.
What is heretical about novel new genes arising out of junk DNA? Molecular biologists have known for many years that so-called "junk" DNA played a number of roles; regulatory, and that most certainly novel genes could arise.
There is a small percentage of biologists which really, really would like acquired traits to be heritable (as a work study job in college, I worked in the lab of one of them, and we were cautioned not to talk about his theory outside the lab).
Every so often, one of the proponents of the idea of heritable changes due to environmental pressure, or more formally, either Lysenkoism or Lamarckism, tries to find a mechanism that could make it work. Even though it's never been demonstrated (the biologist in the lab I worked at was attempting experiments with, among other things, chelodina longicolis diets, to force physical changes, which he hoped the offspring would inherit, even though not on that diet).
This theory is what's known as "soft inheritance".
The main premise for its development in the first place was that Joseph Stalin was all pissy about genetic being a non-Soviet idea, and wanted an nice, Soviet alternative that better fit the ideology he put forth. This actually influenced a lot of decisions in Soviet agriculture that didn't work out badly enough that they ended up importing wheat from the West.
The last go-round was trying to use introns as a mechanism whereby he introns were involved in making traits heritable (and before that, it was endogenous viruses, such as PERV - Porcine Endogenous Retro Virus). Those were the main ones. The've also tried to explain it with varying degrees of gene methylation, and so on. Todays flavor is non-coding DNA (the correct scientific name for "junk genes").
Unless the can demo it in plants, mice, or fruit flies, etc., don't expect that the idea will go anywhere directly.
The sad part is, if they had concentrated on the punctuated equalibria model, which the article mentions, instead of trying to explain it as a short scale inheritable phenomenon, the might have had a really great argument.
(Yes, I am in the 90% who are skeptical about this, without further evidence and perhaps a demo).