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Scientists Make Fish Grow "Hands" In Experiment Revealing How Fins Became Limbs
An anonymous reader writes "While fossils have long shown that limbs evolved from fins, scientists have shown live in the laboratory how the transition may have happened. Researchers said that the new study published in the journal Developmental Cell offers evidence revealing that the development of hands and feet occurred through the acquisition of new DNA elements capable of activating specific genes."
New fish applaud scientist for hands...
The scientist would give them noses, they'd have something to do on those interminable waits between feedings.
"Of course, we haven't been able to grow hands," Casares told New Scientists
Masturbation will still be dicey, but the kissing gouramis are now hugging and kissing gouramis. My work is done!/p?
(Phil-Ken-Sebben)balance the scales...Ha Haaa!(/Phil-Ken-Sebben)
"I don't want more choice, I just want nicer things!"
-Jennifer Saunders as Edina Monsoon
....or you don't have a good understand of what happened.
I for one, welcome our tool using piscine overlords.
So, the hand genes were just sitting around, waiting to be 'activated' by specific DNA?
I think that means that either Intelligent Design is real or we don't have really good terminology to describe what actually happened.
According to the article, the fish embryos continued to grow for 4 days, developing autopods, a precursor to hands. Then they died.
Hilariously enough, this article which is headlined "Scientists Make Fish Grow 'Hands'", contains a quote from one of the scientists involved, "Of course, we haven't been able to grow hands." Basically, this isn't intelligent design, it's exactly how evolution is described to work: You have existing code for fins, a slight modification of which appears to cause differentiation into autopods. This particular change is only one piece of the puzzle, so it wasn't a viable modification.
So, the hand genes were just sitting around, waiting to be 'activated' by specific DNA?
Kinda maybe but not really? There's no gene for hands. There are genes involved in growing those tissues which comprise limbs, which are in turn controlled by other genes. Control those genes one way, you get fins, another way, you get "hands". The controlled genes were already present in the fish, and being used to make fins. Add a new mouse gene that controls those other genes a different way and you get something more like a hand.
As a ridiculously coarse analogy, it's like saying the standard C library has the code for a chess game because if you take a tic-tac-toe game and then re-arrange a bunch of the code that controls how the stdlib functions are called you get chess instead. Yes there are important pieces being re-used but there's more to it than that.
There's no problem with the terminology, and absolutely no need to resort to ID to explain this. Our bodies re-use the chemical machinery of life forms from billions of years ago. Just in different ways. Evolving new mechanisms for controlling that machinery is still evolution.
The enemies of Democracy are
Was there a thunderstorm raging outside when this experiment was conducted?
This just seems like the kind of experiment that would be conducted with a thunderstorm raging outside.
Just saying...
First, they didn't actually manage to grow hands. The closest they were able to achieve was "autopods", a precursor somewhere between hands and fins. The cause of this difference was a transplanted mouse gene which increased the production of a certain protein involved in selection and development of different kinds of tissue.
The real lesson from this is that small changes in DNA can have large effects on physiology. A bit more of a certain protein at the right point in development and you get autopods instead of fins. A few other minor changes and you might even get something approaching real hands.
It isn't that fish have unused DNA lying around which can be "activated" to produce hands; rather, the genetic codes for fins and hands are very similar, perhaps differing by just a couple of mutations. This similarity is evidence in favor of common descent. Why would a "designer" put in the effort to make the DNA so similar? No doubt, if our own experience as designers is anything to go by, it would be far easier to achieve ideal fins and ideal hands without that constraint. Hands and fins differentiated only by the presence of a few specific proteins is perfectly consistent, however, with inherited genetic traits and natural selection.
"The state is that great fiction by which everyone tries to live at the expense of everyone else." - Bastiat
So, the hand genes were just sitting around, waiting to be 'activated' by specific DNA?
No. But this is like a game of telephone. It starts and ends like this,
1. Scientists try to do some experiments to see if they can manipulate genes to see which ones differentiate limbs from fins. You know, since evolution says fish => land. (also land to fins, like whales)
2. After lots of work, scientists get a 4-day embryos that die that have different shaped fins, like autopods. So they found gene that may be a candidate.
3. Scientists communicate to press "Of course, we haven't been able to grow hands!"
4. Slashdot links to an article "Scientists Make Fish Grow Hands!!!!!!"
5. you,
I think that means that either Intelligent Design is real or we don't have really good terminology to describe what actually happened.
6. Scientists: "WTF?"
I guess next week in the news, "Scientists discover green man on Mars!!" and then someone will poast "It is a sign of creator!" and will be modded +5 Insightful.
the genetic codes for fins and hands are very similar, perhaps differing by just a couple of mutations
Except for the fact that while the effect of the transplanted gene was relatively small - an increase in the quantity of a protein - there is nothing saying that the code of the mouse genes which produced the change was "just a couple of mutations." My guess is that the scientists probably imported at least several Kb of already-functional code into the fish genome to produce the marginal change in the protein production. Could be more, could be less.
Saying that the genetics are similar because the effect is similar is akin to going, "Hey, this custom Cinnamon theme on Fedora looks a whole lot like Windows XP - it must be just a few tweaks to get from one to the other!" The underlying code might be similar, or it might not, (In the case of Fedora and Windows XP, it is not) but the presumption of code similarity from product similarity is unfounded. Likewise, the presumption that the functional mouse genes are just a simple tweak or two away from functional fish genes is nonsense. In this case, they might be, or they might not, but there is simply no way to make that judgment based on the effect the code produces.
Why would a "designer" put in the effort to make the DNA so similar?
Code similarity is far from a "constraint." Libraries, modularity, and code reuse are the bread-and-butter of effective and efficient programming. Why make something similar? As a designer of code, I have an answer - because if similar code works in similar cases, then you don't have to bother doing it all twice, ten, or ten thousand times, saving work and reducing the likelihood of error or corruption.
Of course, that doesn't support Intelligent Design. However, claiming that experience designing code suggests that it would be easier to re-implement a feature from scratch for every use case rather than to re-use code is a bad idea.
On a related note - Hey, let's make this an argument about religion on a tech news site, right where arguments about religion belong! Again....
My guess is that the scientists probably imported at least several Kb of already-functional code into the fish genome to produce the marginal change in the protein production.
I see your guess and raise you actual science. What they did, from the article, was take a gene the fish already possessed and multiply it. The fish already produces this protein, but with fewer copies of the gene. Increasing the number of copies, and thus the amount of protein produced, resulted in autopods.
Saying that the genetics are similar because the effect is similar...
I didn't say that. We already know that the genetics are similar, because we've sequenced the DNA of a number of organisms and determined that they're really very similar, even when the organisms appear quite different. Plants and animals, for example, share far more DNA than one would naively expect. What I said was that the fact that a small change in the expression of certain proteins changes the development of the fins to something much closer to hands is consistent with common descent. It shows how small changes over time could have changed fins (or fin-precursors) into hands. That this actually occurred requires other evidence, which we have from a variety of sources.
Code similarity is far from a "constraint." Libraries, modularity, and code reuse are the bread-and-butter of effective and efficient programming.
No argument there, but where is the modularity in DNA? Where are the boundaries between the libraries and the rest of the organism? Code reuse is possible because we carefully avoid making every piece interact with every other piece. We deliberately restrict the ability for small changes in one are to have global effects on the rest of the program, preferring to create small, self-contained modules with well-defined interfaces. DNA is just the opposite: a single huge parallel program, with patches layered on top of patches, and no organizing structure to be found anywhere. What it most resembles (for obvious reasons) is the output of a genetic algorithm, the difference being that genetic algorithms are configured with fitness functions to achieve specific goals, while natural selection has no goal apart from the survival of the genes.
On a related note - Hey, let's make this an argument about religion on a tech news site, right where arguments about religion belong! Again....
You're the one that brought up religion. Up till now, we were discussing common descent ("evolution") and Intelligent Design, a term invented specifically to avoid the religious connotations of Creationism. However, you're probably correct that it's more honest to classify ID as religion rather than science.
"The state is that great fiction by which everyone tries to live at the expense of everyone else." - Bastiat
There are actually gene sequences for example in Dolphins that can grow "feet" but are simply deactivated and no longer used. These are simply remnants of previous species that used to walk on land. So actually these dormant genes actually support evolution.
Scientists have long known that consumption of (sufficient quantities of) Koskenkorva can make Finns become legless.
Although strangely, when in this state, we tend to call them "our 4-legged friends" as they tumble off the ferry. So maybe they were gaining two legs after all.
Also FatPhil on SoylentNews, id 863
They're just trying to take credit for naturally evolved fish with hands found in the ocean at Fukushima.
Next thing you know, they'll try to take credit for creating Godzilla too.
Shameful...
Regarding "code reuse", a perfect creator wouldn't need to worry about abstractions and "generic" libraries: he/she/it would make each item with what it needs and only what it needs. Abstractions are largely to help save human developers time and effort under our limited abilities, not to streamline the code-base.
Then again, "omnipotent" and "perfect" are not necessarily the same thing. Maybe "God" is a Linux admin-like being running us a simulation/emulation. He/he/it has omnipotent power from our perspective because he can change or delete any parts of the simulation that he wants. But this doesn't necessarily make him "perfect". He may make mistakes or be sloppy in some areas.
(Don't tell him I said that, otherwise he may click on my "cancer" check-box or something.)
Table-ized A.I.