Scientists Create Synthesized DNA Bases 125
Iddo Genuth writes to tell us that researchers at the Scripps Research Institute in San Diego have created two artificial DNA bases in an effort to "expand biology's potential." "In the future, [chemist Floyd] Romesberg envisions manipulating the genetic code of bacteria in order to assemble better drugs or even man-made proteins. Until now, the bases only work in bacteria, so human augmentation is currently not possible. Another option is to use alpha and beta to help construct nanomachines to be used for drug delivery. 'This is like jumping from the Stone Age to the Bronze Age,' Romesberg says. 'It takes time to figure out how best to use metal.'" Update 18:10 GMT by SM: Roger writes to share the NewScientist link with a bit more information. There is also the original release text for consideration.
Follow the link at the end of the article (Score:4, Informative)
There is a more technical explanation in the link [scripps.edu] at the end of the article.
We'll get beyond DNA (Score:1, Informative)
Still missing critical information (Score:5, Informative)
For those of you who forgot your biology, 3 DNA consecutive DNA base pairs (called a codon) are translated into a single amino acid. (Khorana, Holley and Nirenberg won the 1968 Noble prize in medicine for figuring this out and determining the mapping [codondevices.com] from base pairs to amino acids)
So, after reading the technical article [scripps.edu], it says that DNA polymerase can bind to the new base pairs (allowing it to replicate), but it doesn't say what amino acids (if any) these new base pairs code for. That's important information because this alleged breakthrough is useless if it doesn't so something useful where proteins are concerned.
Re:I might be wrong but (Score:3, Informative)
Has this not already been posted?
Yes, it has. [slashdot.org]
Tagged oldnews.
Re:These are bases not amino acids (Score:3, Informative)
TFA's TFA mentions information storage in DNA, which makes sense as this basically moves from base-4 to base-5 (The base pairs up with itself, so it's only one new base) thereby improving storage density. They also did some work to evolve a polymerase that replicates the DNA with the new base.
DNA (single strands) and RNA also fold into themselves, and there is some evidence that the folding affects some mechanisms in the cell. Modifying them with these self-binding pairs could probably be hacked up to change the folding patterns. Also, DNA has activation sites and a whole bunch of things other than just the protein coding.
Even without DNA computers, I could see modifying a ribosome to encode a new set of amino acids with the extra base. Also consider, retroviral genetic-therapy style techniques where one of these are inserted into genes to disable them, putting these into introns/extrons to allow for better experiments on DNA transcription, etc.
Interestingly, neither article mentions transcription of this base into RNA, so your concern about amino acids is a little premature.
Re:These are bases not amino acids (Score:3, Informative)
Grossly simplifying, you read off codons (via mRNA, etc.) generating peptides so that you can build up proteins, etc. Some of those codons turn on or off transcription to amino acids.
As noted in the article the fidelity of transcription of these is lower than conventional DNA. So perhaps they could make perfectly suitable markers for areas you want to provoke a mutation at a higher rate, perhaps dropping them into large introns to encourage mutation in those areas.
The 3FB self-pair also expands the vocabulary of base pairs, potentially opening more options for possible nucleases, yielding more ways to cut up the resulting sequences.
The 3FB-3FB pair is symmetric. I'm not sure of any applications of that at this point, but there are people who actually do this stuff for a living who I'm sure can come up with some sort of use for that feature. ;)
Finally the code used need not remain fixed, (i.e. the various mitochondrial DNA codes) so the fact that they don't yield codons in any code we have now, doesn't mean that will always hold. Combined with the fact that transcription error rates are different for them leads to some interesting possibilities.
Re:These are bases not amino acids (Score:2, Informative)
However, this makes it base-6 instead of base-5 or the current base-4. If you recall your high-school biology class, the base pairs only exist in two combinations, but in a total of four permutations. There's adenine-thymine, thymine-adenine, cytosine-guanine and guanine-cytosine. Each permutation codes something slightly different. The new bases would add two more permutations, thus making it base-6.
"DNA Origami" (Score:3, Informative)
Re:These are bases not amino acids (Score:4, Informative)
All the bases do are code for amino acids
That's actually not true. A lot of DNA bases are important in mediating binding to proteins, such as RNA or DNA polymerase, histones, etc. Other bases are important in RNA-based regulator mechanisms, such as anti-terminators.
So the truth is that although we can't really say what we can do with these extra bases right now, the possibilities extend way beyond making new proteins and have many implications for regulation. Why is regulation important? Because differential gene expression is the fundamental principle that allows for cell differentiation and mediating responses to external change.
And for the record, IAAB (I am a biologist).
Re:I want my Vitamin C! (Score:3, Informative)
I don't hate the fruit! I just hate that every other animal in the world can synthesize their own Vitamin C, but we can't!
It's about EQUALITY, not wanting to get rid of fruit. I do like fruit; I have some cherries right now, and they're absolutely divine.
So, in all, I love fruit, I don't want to get rid of it... I just want to get rid of Scurvy...