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."

Comments

All you need to know

[GODISNOWHERE]

From TFA:

"Of course, we haven't been able to grow hands," Casares told New Scientists

Re:All you need to know

[Anonymous Coward]

Slashdot: Scientists make fish grow hands!

Scientists: No we didn't...

Re:All you need to know

[Anonymous Coward]

Title of the FA:

Scientists Make Fish Grow "Hands" in Experiment That May Reveal How Fins Became Limbs

Next line in the FA, synopsis:

Scientists have successfully made fish grow "hands" instead of fins in an experiment that may reveal how animals transitioned to living on land instead of only in water.

First line of the actual article:

Scientists have successfully made fish grow "hands" instead of fins in an experiment that may reveal how animals transitioned to living on land instead of only in water.

and near the end of the article, the line of the OP:

"Of course, we haven't been able to grow hands," Casares told New Scientists

So it's not Slashdot, it's scientific journalists (or maybe just MedicalDaily, but it's so convenient to say just "Scientists" or "Scientific journalists" to make you think that scientists form an hivemind) who take everyone for bloody idiots. Really pitiful...

Re:All you need to know

[slew]

But apparently they grew "hands" (which is apparently what pseudo-journalists call autopods) not hands (sans quotes)...

However, from the truth is stranger than fiction department, a possible reason that it didn't really work might be the lack of a mediating factors like Sonic Hedgehog expression signalling (yes, that's the name of a real gene, which was named after the video game character by the Harvard researchers who discovered it) which has to something to do with making limbs from autopods, but is mostly used in the formation of scale structures in zebrafish.

Re:All you need to know

[argStyopa]

To be fair, the article ITSELF is pretty confused.

1st sentence:
"Scientists have successfully made fish grow "hands" instead of fins in an experiment that may reveal how animals transitioned to living on land instead of only in water."

Near the end:
""Of course, we haven't been able to grow hands," Casares told New Scientists..."

So I'd submit that the summary being a little confusing isn't really the summarizer's fault this time.

Re:Bizarre

[LateArthurDent]

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.

Re:Bizarre

[JesseMcDonald]

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.