Book review: Creation, by Adam Rutherford
Creation: The Origin of Life/The Future of Life
by Adam Rutherford
The DNA molecule is a double helix in which the strands run in opposite directions. So how better to celebrate our growing confidence in understanding the origin of life and DNA's synthetic potential than two books in one both called Creation, one on origins, the other on the future.
Creation is the latest attempt to popularise the theory that life evolved not in a warm pond but in the deep, cold ocean. Students are taught that the vital attributes of life can be summed up in the mnemonic "Mrs Gren": movement, respiration, sensitivity, growth-and-repair, reproduction, excretion and nutrition. But we now know there is a crucial missing factor - one that is the key to the origin of life: constant energy. You can't make a car go by exploding petrol in a cylinder once only. It has to keep on firing.
So what were nature's primal fuel and spark plugs? Mid-Atlantic deep-sea vents discovered in 2000 are the best bet. Here, hot, mineral-rich fluids pour into a cold ocean where a rift opens between tectonic plates. They produce mineral chimneys with porous structures in which these energy processes could have become trapped in a micro-environment shielded from the open sea.
But energy gradients in themselves are not enough. In fact, there are three things that have to come together to produce free-living life-forms: the energy cycles that now power every living organism, a container cell and a replication process. The first life, according to Rutherford, may not have been cellular at all but merely the contents of cavities in these undersea chimneys. But at some point, the cell had to appear. This is the easy part of the mystery. Cell membranes, made of lipids rather like kitchen sink detergents, self-assemble readily in the laboratory. But it's replication that causes the most problems. It used to be thought of as a chicken-and-egg problem: DNA makes proteins and DNA needs protein enzymes to replicate. So how did this ever start? But the most likely answer is neither chicken nor egg but rather a chegg or an ecken. RNA is an intermediary between DNA and proteins, but it can also replicate itself with no enzymatic assistance.
Rutherford tells his stories with great brio and a disarming line in personal commentary (he was a lab geneticist before becoming a science writer and broadcaster). DNA is a code, a language with only four letters - A, T, C, G, for the bases adenine, thymine, cytosine and guanine - and he cleverly exploits this with telling linguistic analogies.
At fewer than 250 pages, Creation is the perfect primer on the past and future of DNA.
Guardian News & Media