How To Grow a Head

Taco Cowboy writes "British scientists have found a mechanism within our gene sequence that allows the growing of a new head — with brains, etc. The gene is tentatively known as smed-prep, and the information contained in smed-prep also makes the new cells appear in the right place and organise themselves into working structures."

Smed-prep

[oodaloop]

Or smed-prop? TFA says both smed-prop and smed-prep without the capital S.

TFA also says that the gene is in flatworms, while TFS says "our".

Overall, though, best slashdot summary ever.

hmmph, sensational

[Gnaythan1]

From what I gather, they figured out the gene sequence in flatworms for growing another head for a flatworm, and can do so consistently.

Since our genes are similar, they probably can figure out where the genes for growing a human head are, and *might* be able to use that info for regenerating damaged brain tissue

No zaphod's anytime soon.

RTFA ? Why would we want to do that ?

[Anonymous Coward]

This is actually about a flatworm's ability to regenerate from serious injuries, not specifically about growing heads.
They claim they've found the genes responsible for regeneration in flatworms.

The title is "Gene that allows growing a new head identified
Now we just need memory backup - and worm DNA"

Which says quite a bit more than the catchy but non-informative title this article on slashdot has.

Re:Oh Sure

[Jurily]

Good news everyone!

Re:What???

[Anonymous Coward]

Sorry but redneck has a specific connotation to South Eastern U.S. people of the white persuasion. Generally blue collar construction or farm workers. Due to the beating of the sun their necks become sun burned (red) or tanned. Another generalization associated with rednecks are they: hunt, listen to country music, drink beer, and drive a truck.

Re:Yes but can they do it without copying Migranes

[Mindcontrolled]

Been wondering about that, too - my planarian ain't as fluid as it used to be. It might very well be "Prepare for the revenge of your planarian overlords, insolent ape!". It's quite similar in pronounciation, you see?

Re:What???

[jweller]

I realize that in this room, defending the redneck is probably about as fruitless as pissing up a rope, but here goes. My next door neighbor is one of the biggest rednecks you will ever meet, and he will tell you the same. He works a blue collar Union job, loves NASCAR, drives a pickup truck, smokes dope, and swills more cheap beer than you can imagine. He also has been married to the same woman for 25+ years, put both his daughters through College, Worked for the same company for 20+ years and is now a shop foreman, isn't a racist, and is generally the nicest guy you'd ever want to meet.

I think the pejorative most of you are looking for is "White trash"

Re:Yes but can they do it without copying Migranes

[Mindcontrolled]

I was rather aiming at the parasitical nature both groups have in common than at the intellectual capacity. I had to learn, unfortunately, that Planariidae are actual non-parasitic flatworms, which makes the above apology to the poor creatures even more important.

Re:Oh Sure

[biryokumaru]

Note for mods: check Ironix's sig.

Re:hmmph, sensational

[reverseengineer]

In particular, it mostly illustrates that in flatworms, body plan genes can be routinely reactivated throughout an organism's life. Most multicellular animals on Earth have a series of genes known as Hox or homeobox genes whose role is to determine the correct placement of structures on the body- depending on the form of the organism, "structures" can mean things like organs, limbs, eyes, tails, etc. The activity of these genes is so important that they tend to have been strongly conserved sequences throughout time- we have some Hox genes that are very similar to those in flies, for instance. This conservation is helped along by the fact that the Hox genes ultimately work by signaling other genes to work; the signaling cascade functions whether the signal is for the development of insect wings or for bird wings.

According to the paper, the signaling involved in the development of the posterior end of planaria (Wnt/beta-catenin) had already been identified; the discovery of Smed-prep explains how the development of anterior structures (the trunk and head of the animal) are regulated. In addition, they found that the anterior and posterior pathways normally work in opposition (to avoid growing a tail on the head or head on the tail), and by silencing the posterior signaling, then activating head regeneration, a head would grow at both ends.

From what we know of human Hox genes, the picture is not so simple- even at the most basic level of developmental organization there are several genes that direct development of the head, so there isn't a master gene we can reactivate to grow an ectopic head, but many of the same developmental pathways (Wnt, for instance) are the same or similar across organisms.

Re:hmmph, sensational

[nohelix]

While you are mostly correct about this, even in planarians, head regeneration requires a suite of genes. By cutting the animal, those genes are activated and then the RNAi is used to alter their expression patterns. It is not as simple as one gene makes the whole head. Its that this gene is one of several including the Wnt/beta-catenin genes that work in concert to properly pattern the head.

To get the multiple head phenotype, the animal must be cut and in its 'regeneration' expression profile - not its homeostasis expression patterns. Nou-darke causes ectopic (extra) brain formation (in a different species of planarians) and brain region extension (in both species) even in non-regenerating planarians, which is not how this gene (Smed-prep) works.

Note that S. mediterranea has two strains, a sexual (cross-fertilizing hermaphrodites) and an asexual strain (that reproduces by fissioning). This means that the animals maintain adult stem cells that can regenerate an entire planarian (and are the only dividing cells in the animal). This gene is not expressed in those stem cells, but it certainly interacts with them in the development of the ectopic heads.
Disclaimer: I work in a S. mediterranea research lab