What Alters Our Genes

Article excerpt

Byline: Sharon Begley

Was a 'fraud' really a discovery?

For a time, it was the most famous fraud in biology. From 1906 to 1923, Austrian biologist Paul Kammerer reported remarkable results in experiments with the midwife toad. Highly unusual for an amphibian, Alytes obstetricans mates on land, not water, and the males incubate the eggs on their legs, also on land. But when Kammerer housed midwife toads in a hot, dry terrarium, they spent most of their time in a nearby basin of cool water: they mated there, and mom deposited the eggs there rather than having dad carry them. It was odd enough that so intrinsic (and eponymous) a behavior was so malleable. But Kammerer found something else.

Once the tadpoles grew up--and here is where eyebrows all over European science shot up--they mated and deposited their eggs in water. Dads no longer midwifed eggs, even when they did not live in desert conditions. By the fourth generation, Kammerer reported, male toads even had black "nuptial" pads, a trait water-mating toads have (to grasp a female) but midwife toads do not. Thus did Kammerer demonstrate the inheritance of acquired characteristics, the then- and still-discredited idea that a new behavioral trait (such as reproducing in water) or anatomical one (nuptial pads) can be environmentally induced and passed on to progeny, despite the progeny's never having been exposed to that environment.

Other scientists were dubious. This was before the discovery that DNA is the molecule of heredity, but basic Darwinian and Mendelian theory held that traits are inherited intact from mom and dad, and that the experiences a parent has cannot alter the genetic material in eggs and sperm. Indeed, one of Kammerer's critics found that India ink had been injected into a toad, creating faux nuptial pads; on Aug. 7, 1926, a paper in Nature suggested that Kammerer had committed fraud. Six weeks later, he committed suicide. Arthur Koestler made the saga the subject of his 1971 book, The Case of the Midwife Toad.

Despite attempts here and there to restore his reputation, Kammerer's name became synonymous with science fraud. But in a fascinating new analysis, biologist Alexander Vargas of the University of Chile reaches a far different conclusion: that Kammerer was in fact the discover of a phenome-non called epigenetics, in which genes are silenced by--and here I'm simplifying, but only a little--experience. …