The 'omics' revolution

The ‘omics’ revolution that has taken place in biology over the last few decades promises to yield so much. Yet undoubtedly we will have to wait a while before this promise is kept. The various human omic maps – genomic, proteomic and in time the epigenomic – have, in so many ways, prompted more questions than they have answered. And this of course is a wonderful thing: an answer has to quickly defer to a raft of further questions – that is how science advances. But there is one specific question that has become particularly intriguing over the last few years – that of epigenetic inheritance. Now, back when I was at school – university even – the prevailing thinking was that acquired traits could not be passed on to the next generation. It was a central tenant of biology that it was the genome, and the genome alone, that took care of all things heritable. The A,T,C and G of the matter was the final word in intergenerational transfer. As humans, our 3 billion base pairs were seen as a string – literal and metaphorical – tying together our ancestry in isolation from the behavioural ticks and traits picked up by each generation. My, how things have changed – the rise and rise of epigenetics has opened a door previously considered closed, locked and bolted. A door that opens onto the world of Lamarckism and ‘soft inheritance’ – the school of thought which holds that acquired characteristics can be passed on by organisms; characteristics which couldn’t possibly be hard wired in genome.

It was a central tenant of biology that it was the genome, and the genome alone, that took care of all things heritable. The A,T,C and G of the matter was the final word in intergenerational transfer.

It is an idea which since the advent of modern evolutionary synthesis has been openly ridiculed. But now, even the staunchest Neo-Darwinist must begin to recognise the winds of change as the epigenetic evidence mounts around them. Evidence like last year’s Nature Neuroscience paper in which Brian G Dias of Emory University in the US claims to show that mice can pass on conditioned fears to offspring.  This is classic Lamarckism – after all what could be more acquired than a fear? Now, the paper has attracted some critics but it is by no means the only evidence available for what is becoming a Neo-Lamarckism movement. There are studies showing the inheritance of adaptive responses in feeding behaviours in chickens, the passing on of non-DNA coded viral resistance in nematode worms and even the alteration of gene function in the offspring of human populations who have experienced starvation. Through epigenetics, it seems as if Lamarckism has ceased to be a rude word in evolutionary science circles. The process of passing a set of characteristics and instructions from one generation to the next is more complex than either Darwin or Lamarck could have foreseen ­– and now it appears as if epigenetics allows both of their ideas to play a role in our contemporary thinking on the great flow of life.