Posts Tagged‘dna’

Know Thyself, Genetically Speaking.

The body is a machine, one that consists of innumerable complexities of which modern science is only just beginning to get a grasp on. Still even with our admittedly limited understanding of how many of the bodily functions work we’re still able to figure out how to optimize its performance at various tasks. To that end I’ve personally read through reams of research to find out what I can to do maximise many aspects of my life, from my fitness to my cognitive faculties and even to my skills as a gamer. Of course my process lacks much of the scientific rigour that I’ve come to admire so more often than not I’ve found myself pursuing something without doing the right amount of research into it.

23andmekitOne of the many things that’s been on my to do list for a while was to get my DNA sequenced by 23andMe to find out what my genetic profile is like when compared to the rest of the world. Whilst I’m already somewhat aware of the health risks that run in my family I’ve always thought it would be good to backup the anecdotes with a little bit of data, even if it was only a single sample point. I’m also lucky enough to have a wife who understands biology on a level that far surpasses mine so the possibility of me finding out that I have a propensity for a rare genetic condition and flying into a wild panic are somewhat diminished.

However it seems that others aren’t so lucky and upon finding out the results of their 23andMe test are seeking treatments for conditions which may be completely unnecessary. This has since prompted the FDA to serve 23andMe with an enforcement action, essentially a cease and desist order giving the company a couple weeks with which to comply with them or face the consequences. Honestly when I first heard about it I was wondering why the FDA would bother targeting them, indeed I thought the kinds of people interested in such data would be well equipped to interpret it, however reading over one particular case showed that 23andMe could stand to use a little more rigour.

Of course the big issue here is people using this data in a vacuum and failing to consult with others to get clarity on what the numbers mean in the real world. My sister in-law found herself in a similar situation recently when the doctors refused to guarantee her child would be free of downs syndrome. The reality is that it’s simply something that we can’t rule out, no matter how good the indicators are, however when the chances are on the order of 1 in 100,000 or greater you have to understand that the risk of it actually happening is quite low. 23andMe results need to be taken in a similar light and in the event should they predict something horrific the next stop should be a genetic counsellor, not the surgeons knife.

I still plan to use the service one day as whilst my primary focus would be looking for potential treatments to improve parts of my life I’m also very interested to see what statistics has to say about the things locked away in my genetic code. Whilst I’ll likely research anything that I feel might be a threat I’ll be sure to temper that research with advice from people more qualified on this area than me. Perhaps this is something that 23andMe should look into doing as whilst it’s nice that they don’t alert you to potentially life changing facts without warning you first getting some context from a real person would probably go a long way to solving their problems with the FDA.

All That We Are is Contained in 5% of Our DNA.

I’ve always found it fascinating just how much commonality there is between us and many other life forms on earth. The explanation is quite simple: certain biological features are the most suited to the world that we live in and thus give the highest chance of survival and procreation. Still even with that fact in mind I still marvel at how much in common we have with even the most bizarre creatures and it gets even more intriguing when you go down to the DNA level. It’s been well known for a long time that we’re genetically very similar to primates to the tune of something like 95%.

One of my favorite astrophysicists (yes I have several)  Neil DeGrasse Tyson made a fascinating point about that small genetic difference (skip to 7:35, although the first point is amazing too):

http://www.youtube.com/watch?v=rDRXn96HrtY

All we are, all the stuff that differentiates us from the great apes is contained in that small difference of DNA. The idea then that another form of intelligent life could be that different from us again really is fascinatingly disturbing as from their point of view we’d be little above cattle to them. You’d hope though that past a certain level of intelligence you’d have some respect for any form of life (like many humans do) but our history has shown how even intelligent species can regard their own as beneath them.

Now if you’ll excuse me I’ll just go and work my way through this existential crisis I’m having.

Arsenic Consuming Microbes: Life Not As We Know It.

I was just about to knock off one of the many RSS feeds I had a massive backlog on when I noticed an article about NASA making a pre-announcement about a press conference they were going to have today. Usually this stuff isn’t front page news but this one had just the right combination of words to send us space nuts (and a good chunk of regular people too) into wild speculation about what NASA might have found. Even more interesting was the fact that one of my friends sent me a rabid SMS directing me to the same article. Something told me that whilst this wouldn’t be your run of the mill NASA press conference there was something big on the horizon, leaving my mind to buzz around all the possibilities.

NASA was not one to disappoint on this occasion.

Researchers at NASA’s Astrobiology Institute have discovered a microbe, native to California’s Mono Lake (a highly inhospitable place), that can survive and thrive by replacing one of the essential building blocks of life with an element that’s highly toxic: arsenic. The bacteria, known as GFAJ-1, was known to be arsenic resistant but researchers took it one step further by depriving the microbes of all phosphorus and flooding their environment with arsenic. The result was that not only did the bacteria survive they thrived, continuing to multiply as if nothing had changed in their environment. Further analysis of the bacteria showed that they had incorporated the arsenic into their DNA where the phosphorus should have been. This throws so many things into question and will change the way we search for alien life out in the universe.

The space and science news sites are abuzz with the implications of the discovery and what it means for the future of astrobiology. The news was so big that it even made the morning news here in Australia something that even the shuttle launches struggle to accomplish. Whilst this announcement isn’t as fantastical as some had hoped for (first contact being amongst them) we’re still at a turning point in our understanding about how life formed here on earth and how it can form elsewhere in the universe.

The discovery is interesting as prior to finding these microbes all life on earth has needed to use 6 building blocks in order to survive: carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur. Arsenic is just below phosphorus on the periodic table so it shares quite a lot of properties with it and that similarity means it can be substituted into some biological reactions. However arsenic is far more reactive than phosphorous and this means that it is highly toxic to almost every life form on the planet. This bacteria however seems to have developed the ability to use arsenic when it is in a phosphorus poor environment and even has the ability to switch back to phosphorous should it become plentiful again (it actually seems to prefer it).

As with any big discovery this one is not without its critics. Steven Benner, a chemist from the Foundation for Applied Molecular Evolution, makes the point that whilst these bacteria were phosphorus starved there were traces of it available. Enough possibly to sustain these bacteria in the arsenic rich environment. Additionally should these bacteria be incorporating arsenic into their DNA it would be in the form of a arsenate, an ester of arsenic. Such a compound would hydrolyse in water making such arsenate based DNA unstable. He hypothesises that the arsenic is being used in some other fashion, possibly in a way that we do not yet understand. The research is of course continuing and will address these concerns.

We’ve known for a long time that life can develop in places we’d long thought it was impossible to do so but this discovery is something on a whole new level. Showing that a life form, even if it’s a simple one, can replace one of the fundamental building blocks of life with something thought to be toxic means we have to rethink the way in which we look for life here and out in the vastness of space. The prospect of finding life on other planets and moons here in our own solar system just got more possible as our understanding of how life can thrive undergoes a radical paradigm shift. I can’t wait to see how this develops and I’m sure this isn’t the only bacteria out there capable of feats like these. Who knows what kind of alien life we’ll find right here in our own little rock called earth.