What makes cells tick? Genes or mysterious fields we can't detect?

8 July 2009

In the spirit of scientific wagers that saw Richard Feynman bet against micromachining and Steven Hawking reject the idea of Cygnus X-1 harbouring a black hole, Professor Lewis Wolpert has staked a case of port that maverick biologist Rupert Sheldrake is wrong about the role of the genome in determining the fate of living organisms.

However, it is a bet that Wolpert expects he will lose, not because he believes he is wrong but because computer technology and human knowledge will not be able to establish his position in 20 years' time when the outcome of the bet is to decided.

"My guess is that I have been quite generous," Wolpert told me on the question of timescale. It could take 40 years, not 20, for science to work out how to predict the shape of an organism from the genetic information contained in its egg. "It is really a matter of being able to develop the molecular biology needed to understand the interactions within the cell: the way in which all the proteins interact within the cells."

Not only that, there is the issue of how much compute power will be needed to do the prediction. "It will be immense," said Wolpert, who reckons 40 years is a more likely timescale in which to prove him right.

The full arguments from both Wolpert and Sheldrake are published in this week's New Scientist. The release that has gone out from Sheldrake's publisher, Icon Books, makes it look as though Wolpert had narrowed the scope of the bet too far. "[Wolpert] is convinced that it is only a matter of time before all the details of an organism can be predicted on the basis of the genome," it read.

That rang a few alarm bells as, if that meant the genome in terms of a sequence of DNA, the chances are that there is not enough information in that to be able to predict much with any accuracy. This looked to be a bet Wolpert is guaranteed to lose. But Wolpert explained that, from his point of view, the bet takes into account the additional information that an egg might have and not just the sequence of DNA in the genome. "It involves the entire chemical constitution of the egg."

Wolpert is not a big fan of epigenetics as a means of inheritance but acknowledges that the action of proteins on DNA, often silencing genes by adding chemical side chains, or by wrapping the DNA around them, influences the behaviour of the cell.

The bet stems from a March debate at the University of Cambridge between the two in which Sheldrake maintained the position that the genome cannot determine how an organism will form. "It provides nothing more than the code for making proteins," said Sheldrake. His argument is that for cells to differentiate something else is needed. For Sheldrake, that something else is 'morphic resonance': the result of fields formed by biological material that communicates form and function to similar creatures.

That DNA provides the recipe for proteins, and only does that, is no problem for Wolpert. It's not just proteins that DNA templates for, RNA is the initial product and, in anything above bacteria, an important product for cell development. I don't think Sheldrake and Wolpert would disagree on what DNA generates, the difference lies in the emphasis.

For Sheldrake it is "just proteins" (and RNA). For Wolpert, that's all you need. Emergence takes care of the rest. It is in the complex interactions between proteins, DNA and RNA that organisms grow and develop. Nothing else is needed. Our only problem right now is that we cannot predict precisely how an organism might develop purely from the mixture of DNA and proteins in an egg, assuming we could, in the first place, take a snapshot of all those things.

In the March debate, Sheldrake argued that Francis Crick and Sidney Brenner had made all these deterministic claims before, back in 1963. And then, the timeframe was only ten years. What's so different now?

Clearly, Brenner underestimated the complexity of the job of using genetics to predict development. Crick took on consciousness, which was an even harder thing to explain. But, in that time, molecular biology has answered a good many questions about development even if, at the same time, it has raised many more.

Sheldrake's position boils down to an argument that fields we cannot detect directly are somehow able to act on biological material, and biological material alone, in apparently complex ways. In fact, anything that does not have an immediate explanation in the molecular world simply complicates the field part of the equation. And, in Sheldrake's view, this is a field with memory. That's some field.

2 Comments

I doubt the decoding will be done in 20 years, and not necessarily due to the complexity of protein / DNA / RNA / cellular DNA interactions.

I'll ignore methylation patterns (which switch certain genes off).

But, people don't need to know how everything interacts to get to the information they need. People want to know what bad things can happen to them - see Craig Venter - and the rest is not essential.

I do worry about the psychological aspect behind it all though - I don't want to know what untreatable diseases I'm prone to getting. And I'm not alone - the inventor of the Huntingdon's test has a 50:50 chance and refuses to take it.

They'll have to deal with methylation, acetylation and all the other -ations. 20 years is a tall order. The Digital Human project assumes mid-century, which falls in with Lewis Wolpert's projection. For some things a simple SNP check will make a reliable prediction; for a bunch of other bad things, it may call for a full simulation. We just don't know yet. I have little faith in the 23&Me analysis to identify much of use, beyond the conditions that are trigged by the inclusion or absense of a single gene.

It's worth bearing in mind that the bet was triggered more by Sheldrake's position than by Wolpert. The problem is that, to disprove morphic fields, you have to establish beyond doubt that the genetic interactions are all you need. The bet assumes a constant, controlled environment for a particular species of nematode worm and focuses on development rather than identifying defects.

But, the way the bet is set up, it makes it looks as though genetic determinism is everything - but it isn't. The factor that environment plays is still hard to determine.

I think the psychological aspect is a concern but people already have to deal with those, where they know that Alzheimer's or heart disease runs in the family. I think a bigger concern is the impact on insurance and healthcare as public medical budgets are slashed. Do you lose protection if you don't follow the pre-disease treatment plan? Do you get any protection at all?