Leroi writes beautifully, charging his case histories with drama and pathos.

Time Out, London

The best way to understand how the human body duplicates itself is to look at what happens when that process goes wrong and the inscrutable syntax of our genes becomes scrambled. 'We must find mutants' writes Leroi, a Reader in Evolutionary Developmental Biology at Imperial College, and find them he does, scattered across history: conjoined twins; giants and dwarves; hermaphrodites; women with supernumerary breasts; children who, like Homer's Cyclops, are born with a single eye in the middle of their foreheads (and so a single cerebral hemisphere: 'holoprosencephaly' is the technical term, its cause a mutation in a gene called — and I'm not making this us — Sonic Hedgehog).

Of course we're all mutants, up to a point — the point where the diversity that we would normally celebrate becomes a handicap, and we become obliged to distinguish between what Leroi calls 'frank errors' and 'mere inconveniences that occupy the inter-tidal between the normal and the pathological.' Establishing a norm, or more controversially, a benchmark of perfection is futile. 'The only reason to say that one genetic variant is "better" than another is if it confers a greater reproductive success on those who bear it.'

Leroi writes beautifully, charging his case histories with drama and pathos. It's heartbreaking to read about Shwe-Maong, a Burmese hills-man who suffered from hypertrichosis (chronic hariness) and whose family were kept as curiosities by the Burmese royal court. When the British conquered Upper Burma in 1855, his similarly hairy daughter Maphoon, fled with her son into the forests, where they were captured by an Italian Army Officer who persuaded them to travel to Europe. 'And it is there,' writes Leroi, 'that we hear the last of [them], exhibiting themselves at the Egyptian Hall in Piccadilly and then in Paris at the Folies Bergère.

File under: not to be read during pregnancy.

John O'Connell
Time Out, London (June 2-9 2004)