I am surprised that Georgina Ferry should be shocked that the protein-making ‘words’ in our genome only comprise about 1.5% of it, albeit there are 100,000 human proteins for them to encode. To call the other 88.5% ‘junk DNA’ seems to ignore the fact that I am not (nor is anyone else) just an amorphous blob of protein. We have hair at one end and toe-nails at the other, and an unimaginably complex array of tissues and organs in between, all arranged in their proper places so as to function as a whole.

So, somewhere in that 88.5% there must be genes for hair and toe-nails, arms and legs, brain (with its 80 billion or so cells), spleen, heart and everything else. That is, the proteins have to be given a very precise three-dimensional order, not just an existence. The shocking thing is that that can be done with so few genes, and that the forming body usually comes out in full working order, in spite of the myriad ways it could go wrong.

Ferry's article is full of interest, and is not the only one in which structure is ignored while composition is accounted for. I have read many others with the same apparent blind spot. The specification of bricks and pipes is a small part of an architect’s job: the main part is indicating how they are to be put together to make a building.

Alasdair Livingston
Merton, 1947