Four new DNA letters double life’s alphabet

www.nature.com...

The DNA of life on Earth naturally stores its information in just four key chemicals — guanine, cytosine, adenine and thymine, commonly referred to as G, C, A and T, respectively.

Now scientists have doubled this number of life’s building blocks, creating for the first time a synthetic, eight-letter genetic language that seems to store and transcribe information just like natural DNA.

For a long time, scientists have tried to add more pairs of these chemicals, also known as bases, to this genetic code. For example, Benner first created ‘unnatural’ bases in the 1980s. Other groups have followed, with Romesberg’s lab making headlines in 2014 after inserting a pair of unnatural bases into a living cell.

But the latest study is the first to systematically demonstrate that the complementary unnatural bases recognise and bind to each other, and that the double helix that they form holds its structure.

The letters of DNA pair up because they form hydrogen bonds: each contains hydrogen atoms, which are attracted to nitrogen or oxygen atoms in their partner. Benner explains that it’s a bit like Lego bricks that snap together when the holes and prongs line up.

By adjusting these holes and prongs, the team has come up with several new pairs of bases, including a pair named S and B, and another called P and Z.

The researchers then conducted a series of experiments that showed that their synthetic sequences shares properties with natural DNA that are essential for supporting life.

I've got mixed feelings about this kind of work. The potential for huge medical advances playing with and creating DNA makes it pretty amazing work. But the potenital for screwing something up and creating something that could potentially wipe us or all life on earth exists too. We still don't understand a lot about DNA and life in general, but it seems like everyone is rushing in to play with it. Ah well, hopefully the positives end up outweighing the negatives, because some of those negatives could be fairly horrifying.

a reply to: dug88

I guess it's part of our natural evolution to be able to alter or create DNA but the science has the potential of misuse by the unscrupulous , no doubt good things could come from it but good things came from Nuclear technology.

a reply to: dug88

AI learning to modify its own code. Something is lost between synthetic and natural processes. I don't foresee this going well and may be the start of an actual Eugenics war.

Interesting thread!

Pretty interesting, but they apparently still have some work to do. They were able to get the synthetic DNA to synthesize RNA, which can then be translated to proteins. However, they have not tested it with DNA polymerase to see if the synthetic one can under go self replication.

One question I would have tho....so they tweaked the chemical structure of the original nucleotides to make 4 new base pairs. Amino Acids are coded for by sets of 3 of these 4 base pairs, for example, TAT or TAC code for the amino acid Tyrosine. So if they tweaked to the original base pairs, do the codons change in what amino acids they code for? still interesting tho.

creating something that could potentially wipe us or all life on earth exists too.

I get the feeling that with this stuff there are outcomes that are far worse than extinction.



Also this kind of work could lead to the thought put forth in a thread recently of humans and robots having offspring.

It's NOT a eight-letter genetic code. It's still a four-letter code, but synthetic. It would only be the former if the four new bases hydrogen-bonded with the four natural ones, A, G, C & T. As far as I can see from the synopsis of the research, this has not been demonstrated to occur. There are still only 64 of the corresponding protein-coding codons. it is just that there are 64 new ones. An alternative four-letter genetic code that has been partially demonstrated to be viable does not means that life is based upon an eight-letter code.

originally posted by: micpsi
It's NOT a eight-letter genetic code. It's still a four-letter code, but synthetic. It would only be the former if the four new bases hydrogen-bonded with the four natural ones, A, G, C & T. As far as I can see from the synopsis of the research, this has not been demonstrated to occur. There are still only 64 of the corresponding protein-coding codons. it is just that there are 64 new ones. An alternative four-letter genetic code that has been partially demonstrated to be viable does not means that life is based upon an eight-letter code.

Did you actually read the article? It's right in there...

By adjusting these holes and prongs, the team has come up with several new pairs of bases, including a pair named S and B, and another called P and Z2. In the latest paper, they describe how they combine these four synthetic bases with the natural ones. The researchers call the resulting eight-letter language ‘hachimoji’ after the Japanese words for ‘eight’ and ‘letter’. 

A logical synopsis would be, if they are not readily seen in what we understand today in DNA, then why would they be needed? The saying, "Do not try and fix or modify what is not broken", really applies.

originally posted by: wtfatta
a reply to: dug88

AI learning to modify its own code. Something is lost between synthetic and natural processes. I don't foresee this going well and may be the start of an actual Eugenics war.

Interesting thread!

AYe as soon as they are classed as non-human , we will commit terrible acts upon them

Once you alter DNA you're no longer human, correct?

a reply to: jjkenobi

I'd think that there must be a certain percentage of your genetic code you'd need to alter before you wouldnt be recognised as human .

DNA is pretty good at changing / altering itself based on its environment but it still says human underneath it all.

I'm sure they would implement new laws , where in you alter your DNA beyond 25% of the original base code
then you are no longer classed as human and fall into some other legislative black hole where you rights arent as concrete.

If anything I think it will be like the tick , any humans or Humanity + , would not have the same rights as humans born without DNA alteration.

I think the same will happen with transhumanists .

We are going to kick of all whole new era of Eugenics and wars based on your pure genetics , or whether you are an analogue or digital human .