Friday, 25 March 2011

tMoL: Genotype vs. Phenotype

It's the end of another term, time for me to move on again. I'll be going home soon to write about what's been going on, and there's a lot to say. The talks I did in schools went really well, although there's still stuff to improve on. This lab placement has been really great and I've been enjoying all the other projects I'm involved in. Next up is an unconference, SciBarCamb, which I strongly recommend to anyone reading this blog.

This is a peice I wrote for a friend of a friend, she's doing a course in genetics and was looking for clarification of the difference between genotype and phenotype, it was a bit of a rush job but hopefully it clarifies matters.

In order to live, grow and make more of themselves, cells need to have instructions. These are stored as DNA, which is mostly found in the cell nucleus. Each set of instructions is called a gene, each gene produces a particular protein. The full set of human DNA, the human genome, can make thousands of proteins and each protein performs a specific function within a cell.

Genes are specific DNA sequences (source)
 Different people have different versions of the same gene and hence of the same protein, this is what makes us genetically different. These different gene alleles have different effects within our body. As a simplified example; there is a protein which is responsible for hair colour. If it is functioning properly then you have brown hair. Some versions of the protein do not function properly so there is no colour made, this results in blonde hair. There are various other versions with intermediate effects resulting in all different hair colours. This is a slight simplification, as there are actually multiple proteins involved in hair colour, but it illustrates the principle.

Friday, 11 March 2011

SOS: Save our Science - Yet More Alien Bacteria. Really!

I saw James Watson last night! and I have his autograph. :D He was in London, in conversation with Brenda Maddox, who wrote Rosalind Franklin's biography. It was fascinating, although I have to admit that he was clearly on his very best behaviour and kept the outrageous comments to a minimum. I'd also like to take this as my excuse for any 'enthusiastic' comments in the post below, which is a great peiece of storytelling. This week was also my first outreach talk to school children, I think it went rather well, although I'll be writing much more on that in a few weeks.
OK, so this is another story that I was asked to write (Yay!). Once again there have been reports of alien bacteria in meteorites (that’s the third time in 14 years, if you’re counting).Here is the latest story, I suggest you read it first as it makes what I’ll be saying more surprising. Go on, I’ll wait. Sounds good doesn’t it, highly acclaimed doctor with a paper in a prestigious sounding journal, with authoritative quotes and everything. Not only that but the journal seems to have gone to great lengths to ensure extensive peer reviewing of the findings before publishing. Well, as with many stories that get NASA plastered to them, it’s got a lot of people rather riled up and for a lot of different reasons. Read on and I’m sure you’ll see why.

This is a fantastic story, I’ve never seen so many mistakes made by so many people in so many different ways, it’s quite a feat of engineering really. Also it does go to show that some people really do never learn. The roots of this story lie all the way back in 1997 when NASA scientists reported finding bacterial fossils in a meteorite from Mars.

This astonishing and revolutionary finding was reported by Richard B. Hoover who works at NASA’s Marshall Space Flight Centre. This was discounted shortly afterwards when it became apparent that the structures observed were probably contaminants from the time the sample spent on Earth before being studied. Now some people would learn from such a colossal mistake that was a huge embarrassment for NASA and Hoover personally.

This bacterium from Earth looks strangely like some observed in these meteorites (source)

Hoover, however, is made of stronger stuff. After his error in 1997 I’d like to say that he improved his working scheme, ensuring all samples were properly sterilised and cross checked before announcing proof of alien life to the public. But he didn’t. He returned in 2007, although with less impact (mainly due to lack of a successful publication), to say that he really had found life, this time in a totally different type of meteorite. Thankfully this time he attracted less attention.

Now, to the delight of many, Richard B. Hoover has returned to the public stage, thanks in no small part to the lovely people at FOX news, with another attempt. He’s still looking at the same rocks from 2007 but this time he REALLY thinks he’s got it.