Hi
When would it be valid for scientists to claim that they have created life?In other words what ingredients in nature that constitute the elemental constituents of life would scientists not be permitted to depend on to make the claim that they have created life?
I look forward to your feedback.
2010 it would have been valid:
It’s already done.
Thanks core melt. But the article does state:
“The new organism is based on an existing bacterium that causes mastitis in goats, but at its core is an entirely synthetic genome that was constructed from chemicals in the laboratory.”
Does the claim to have created life count as such if that life form was made from ‘scratch’ based on an existing bacterium?
Perhaps one should distinguish between A-life ‘based on’ other life and 'novel life forms".
March 3 2017
This is interesting:
http://www.stuff.co.nz/science/90024611/Artificial-life-created-in-the-lab
“Cambridge University used two types of mouse stem cells to create a living mouse embryo which formed after just four days. It is the first time scientists have ever been able to create a living embryo without using sperm or an egg.”
The video of Craig Venter describing his team’s work is very good. It is clearer, more accurate and more informative than second-hand accounts filtered through the media. Craig Venter creates synthetic life form | Craig Venter | The Guardian
First, let’s review what Venter’s team actually did. There are two main types of cells, eukaryotes which have a membrane-enclosed nucleus DNA within that: Eukaryote - Wikipedia and the simpler prokaryotes (like bacteria) which have more accessible free-floating DNA: Prokaryote - Wikipedia
Venter’s group took an existing bacterium (a prokaryote) and fully replaced its genome with a synthetically-constructed genome they programmed. By normal definitions they did not “create life” from raw materials. E.g, even a bacterium contains highly complex molecular machinery which they’d have to fabricate: Flagellum - Wikipedia
OTOH normal definitions of what constitutes creating life doesn’t necessarily apply in this case. From one perspective, all functions of the cell are determined by the genome. A new DNA sequence will totally transform the cell characteristics and behavior, much like new software code will totally transform a computer’s characteristics.
Venter’s team constructed from scratch new DNA code of over one million letters, including error correction. They inserted this in the bacterial cell, causing it to “boot up” on their new code, and it immediately assumed those new characteristics – it was in effect a totally new species. They even included watermarks in their code to verify the old code was fully replaced.
Venter said doing this for a more complex eukaryotic cell (ie containing a nucleus) would be far more difficult, but maybe someday they could achieve this.
Eukaryotic cells contain tiny organelles called mitochondria, which themselves contain complex rotating nanoscale machinery: ATP synthase - Wikipedia
If the goal is replacing a existing cell’s DNA with custom DNA “software”, Venter has already done that. It may be eventually possible to do that on a more complex eukaryotic cell. However if the definition is all that molecular machinery must be created from scratch, that is a very long way off. This is obvious from the computer world. It’s much more difficult to design and fabricate a CPU than to create a basic software program that runs on the CPU.
Nonetheless some researchers are making tiny steps toward creating artificial cells from scratch. Note in this article “cell” is in quotes – it’s not really a cell, more like a primitive nanobot: Scientists Create Simple Artificial ‘Cell’ Capable Of Spontaneous Movement | IFLScience
You could argue that a sufficiently sophisticated nanobot would sort of be like a mechanical “cell”. However construction of practical nanobots is also proving more difficult than first envisioned: Why There Aren't Fully Operational Nanobots Just Yet - The Atlantic
What I would mean by it is that someone put some inorganic chemicals (by which I mean the older definition of not coming from living beings) into a pot, stirred well (in a metaphoric sense) and came out with something that metabolized and reproduced.
In that 2010 case, did the scientists author the code from scratch, or merely craft it?
That is to say, at some point they must have needed, for instance, a transcriptase enzyme in their organism. Did they look up the sequence of some existing transcriptase enzyme and copy-and-paste that into the DNA, or did they come up with their own sequence from scratch for a novel transcriptase enzyme? I’m almost completely certain that it was the former. Which makes their work comparable to the student who re-types an essay from one they found in a book. Even if it was the student’s fingers striking the keys, one still wouldn’t say that they created the essay.
Thank you all. Very enlightening.
@Chronos: I’d say it’s more comparable to a student who cut and pasted bits of a dozen essays and wiki articles together, did some rewriting to make the voice more consistent, then sent that in as original work.
The bigger difference is in the scale. They didn’t plagiarize from a dozen articles; more like many thousand.
IOW: impressive, but as you say, not ab initio.
As a comparable question for our OP: How original must an essay be to be an “original essay”? Must every paragraph never have been written before? Every sentence? Every word? How different is different enough?
If I take *Hamlet *and change all the character’s names is that enough? How much more must I do? Is West Side Story the same as Romeo and Juliet? Or merely vaguely similar?
My point being that your original question about life is far more in the realm of philosophy than it is in the realm of biochemistry.
It seems to me the OP is asking if any new life forms have been created from scratch … and not taking an existing life form and modifying it … which it appears to be what happened with the Venter et al study that coremelt posted … given just methane, water and ammonia … has anyone created a life form of any kind?
If we’re looking for life on other planets … it would be helpful to know how life formed on Earth …
As a side note, there’s something really really cool it’s straightforward to do.
You can mutate the ribosomes so they accept 4-base codons instead of 3-base codons. That multiplies the total number of possible codons by 4. You then run through a Python script or something every 3 codon base in an existing genome and convert it to a 4 codon code that is corresponding.
You could make a synthetic organism that has 4 times the solution space to evolve into. It would technically be superior to all life on earth, and it’s not even all that hard to do. It was something nature could never have realistically arrived at, however.
The reason it is superior is you use the 196 additional codon signals to give the organism new amino acids it can use, and you would need to give it the synthetic pathways to make them. It would be capable of making more capable proteins than any other organism on earth. Over a long enough timescale (probably millions of years), if released to the wild and able to survive in a starting niche, your lowly bacteria would probably grow into a superior strain of bacteria that outcompetes everything else. Or, it might get fused with existing natural bacteria, forming some kind of crazy split genome organism.
I’m not at all convinced that such an arrangement would be superior. There’s already room in the genetic code for more amino acids, but it’s not used. I think the simplest explanation for that is that there just aren’t all that many amino acids, or at least, not all that many useful ones. And fitting those 20 amino acids into 256 different codings instead of 64 would mean that you’d have a lot more mutations which didn’t change protein sequences at all, which would probably mean slower evolution.
Meanwhile, you’re also costing the organism more overhead to support the longer genome, and for every new amino acid you add, you’re also adding overhead for the pathways to make and use those aminos. It’s hard to see that you’d get any benefits large enough to make up for the costs.
http://www.nature.com/nature/journal/v464/n7287/full/nature08817.html
Maybe. It’s only a possibility. The thing it shows is that this limitation is one that evolution cannot directly bypass, because in order to do so, it would have to, mutation by mutation, design the computational machinery to turn the codebase of an existing cell into one that uses the new system.
Its a good, solid, concrete example of the kind of barriers that evolution can’t beat as an algorithm (but intelligent design can)
Evolution cannot bypass this limitation it because the machinery would only need to be used once, is very complex, and would not provide any benefit until it is used.
You are correct that a cell that needs another amino acid would probably just repurpose a codon that has duplicate encodings.
The standard academic sarcastic response would be:
Q: When would it be valid for scientists to claim that they have created life?
A: After peer-review.
“Give my creature life!”
After the lightning strike…
I think saying evolution can’t develop this four unit codon isn’t established, not without the specific reasons … at most we can say that the three unit codon is the best economy and this is the form that we find in nature today … and that a four unit codon is very very unlikely to evolve … but the probability is not zero, just very very close to zero …
We have almost no evidence of any kind of the original life forms on Earth and DNA is not well preserved in the fossil record in any case … it’s going to be a reach to say a four unit or even a two unit codon never existed … all we can really say is that a three unit codon works today and provides all the diversity needed for us to find the amazing range of life we do find …
Four unit codon appears that it could evolve … just there’s no need to do so … how many ways are there to combine a couple dozen amino-acids into 2,000 pair chains?
Franken-SHTEEN!
Frau Blucher!
“What hump?”
Actually, I’ve seen studies that suggest fairly strongly that the current genetic encoding did evolve. The authors came up with an objective figure of merit for measuring a genetic code, and found that the one we actually have is better than 99.9% of all possible genetic codes. This suggests that many different genetic codes were in fact tried early in life’s history, and that the one that led to us outcompeted all of the others.