James Bowers PhD
Recently, Prof. Floyd Romesberg and his team managed to successfully insert synthetic components into a DNA sequence. Dubbed "X-Y", these are the first-ever man-made elements to be added to the genetic alphabet. Why is this such a big deal? And, with all the media attention, are we getting just a little ahead of ourselves?
Cet article existe également en français : X-Y : les nouvelles lettres de l’AND trop vite affranchies (Translation/traduction : Pierre-Sofiane Kadri)
Image courtesy of Flickr (by MIKI Yohshihito)
I have quite a few, particularly non-scientist, friends that have been asking me about my opinion on the new “X-Y” discovery. One even tried to convince me that it’s “the greatest achievement in science of our time” without really having the background to back it up. It’s understandable as, in the past month or so, there has been a lot of talk in the media about the insertion of these artificial building blocks into a DNA sequence. Prof. Floyd Romesberg and his team developed this impressive technique at the Scripps Research Institute in San Diego, California. Whilst the method is more of a new type of genetic modification, it’s not quite as “alien” as some journalists have been describing (Romesberg even said so himself!) – so let’s just calm ourselves a little on that front.
The Basic Idea: X-Y
DNA, the blueprint for life, is composed of a specific sequence of “bases”. These bases, or nucleotides, are strung together to generate the DNA sequence, which all of our cells can read - a bit like a biological Morse code. All known life on Earth contains the same four DNA components, referred to as A, T, C and G. These bases exist in pairs within DNA, resulting in A-T and G-C couples. It’s a relatively simple way of storing information that can produce a ridiculously high number of possible combinations and is thus sophisticated enough to drive the biological diversity of life.
Romesberg and his team have managed to introduce two new, synthetic bases, dubbed X and Y, into E. coli (bacteria) cells, with (almost) no effects on their normal life cycle. Their article, published in the prestigious journal Nature, demonstrated the construction of a DNA sequence with one single X-Y pair inserted, compared to many thousands of the four “natural” bases, that could be passed down through the bacterial generations. The important difference being that the researchers designed the X-Y bases such that they bind to one another using hydrophobic bonds, as opposed to hydrogen bonding that exists between naturally occurring nucleotides. Romesberg and his team achieved something fantastic – they added new letters to the DNA alphabet!
As a side point – if you’re as confused as I was about the naming “X-Y”, which instantly made me think of the male chromosome pair; it turns out this name was invented by the media and not by Romesberg or his team. He clarified in a recent interview that the real name is 5/6NaM, although by the looks of it, XY is probably going to stick.
The X-Y triumph
Firstly, nobody really knew if it was even possible. Mother Nature has been so much better at creating efficient, whilst not perfect, organisms than we have. So the question, in part, was whether DNA contained only four bases because it was the most efficient, or even the only possible, way of storing biological information. This work shows that it may not be the only possibility. Secondly, DNA is like an internal recipe book for everything that a cell can produce; this technique could (it’s a long way off!) be used to develop organisms that can produce medically relevant substances in the future and also NEW substances that don’t even exist yet. In that sense, (ethical debates aside) the possibilities would be endless…
The X-Y trump?
So there we have it, yet again science has managed to make a new (AMAZING!) discovery – YAAY! It’s no surprise that it has had a lot of media attention. You can find articles and reports all over the web and TV talking about it. But is this media-driven spectacle also due to the fact that the paper describing the work happened to come within days of the official opening of a spin-off biotechnology company, SYNTHORX? Great timing and great press for SYNTHORX, who will need to convince people as early as possible that this discovery is worth investing in for future development – and there is no doubt a huge amount of work to do! The reality is that a well-funded biotech is probably the fastest route to developing genuinely useful applications.
Science is a wonderful thing and plays an enormous part in our society, although sometimes the media-hype can blow things out of proportion. Let’s face it: good science takes a long time. It will be a long-haul slog before anything really useful comes of this. This is the reason why Nobel prizes are generally awarded to scientists several decades after they made their original discovery - because we simply don’t know how useful something will turn out to be in the future. Whilst the hype is clearly well deserved for the amount of hard work and good science that led up to this point, the real benefits of this discovery will not be known for a long time yet. Looks like we aren’t about to be meeting any small, grey, “X-Y” DNA-containing aliens then (not just yet anyway!).
