I’ve been reading Fritjof Kapra’s book The Hidden Connections. It’s a wonderful book, for the following reasons:

• It references several of my favourite reads of the past year – always reassuring.
• It criticises globalised capitalism – huzzah!
• It contains a superb description of the problems with genetic determinism.

…Genetic determinism?

Well, from what I’ve read so far, genetic determinism seems to be the idea that DNA is the instruction set for defining how your body and behaviour develop. So GD, in a fairly bald, simplified form, says “your genes define you.”

Kapra thinks that the assumption of GD lies behind claims by biotech companies that they’re about to produce a gene therapy for an illness, or that a research group has found a gene for something. He believes that biotech companies trade on this kind of announcement – it represents a well-rehearsed format for a news story, and wins the company publicity, which is good for share prices.

It’s also an assumption behind the popular understanding of cloning: matey takes some DNA off of a sheep, then sort of, well, I dunno, I suppose he puts it in an empty egg cell or something, then puts that up another sheep, and then he’s made this fluorescent sheep or whatever. With the testicles of a spinach.

But there are problems with the idea:

1. DNA doesn’t define anything if you separate it from the living cell: a test tube full of pure DNA will simply sit there until the DNA decays; without support from ribosomes, any number of proteins, in fact from metabolism as a whole, DNA is meaningless. A foetus begins as DNA from its mother and father within the framework of a living cell from mum – the egg cell. Apparently cloning’s far less frequently successful than we might think, because it can take hundreds of attempts to find an egg cell that’s compatible with the clone DNA.
2. The “same gene” can be expressed differently in different species: chimps are almost genetically identical to people, but they appear and behave very differently. The same genes produce different results in different contexts.
3. The “same gene” can be expressed differently at different points in an organism’s life, and in different parts of its body: every cell in your body (apart from cancers) has identically patterned DNA, but different cells behave in very different ways.

It looks like cells define how their DNA works, as well as the other way round, and the new sciences of evolutionary development and systems biology are beginning to unravel and model how this all functions.

Last night, though, I was talking about all this with a couple of friends and one of them said, “Like christianity!” Now, we’d had a bit to drink, and I’m not sure I’m characterising what he said correctly, but I think it went something like this:

• DNA kind of defines the structure and behaviour of the cell, at the same time as the structure and behaviour of the cell define how the DNA is interpreted. During an organism’s development, different types of cell develop, each of which interprets the same DNA in a different way.
• The bible kind of defines how the various denominations of the christian church think and behave, at the same time as different denominations interpret the bible in different ways. During the history of christianity, different sects have developed, each of which interprets the same bible in a different way.

That’s my kind of analogy!

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