On the morning of 2 August 1921, a forty-year-old high-school teacher, Hans Duncker, set off from home through the prosperous and busy streets of the German town of Bremen. Stocky, moustached and bespectacled, Duncker was near the cathedral in the medieval centre of the city when he suddenly stopped in his tracks. Tilting his head slightly to one side, he closed his eyes and listened. People stared as they brushed past, but Duncker was transfixed. Somewhere out of sight a nightingale was singing. No nightingale ever sang in August and certainly not in the middle of town. Perplexed, Duncker made a mental note to come back and locate the enigmatic songster.
He never did, for the following week he met the owner of the mystery bird. Karl Reich, thirty-six years old, was a well-known bird keeper who in his twenties had been the first person in the world to make sound recordings of birdsongs. But it was no record that Duncker had heard; it was something even more extraordinary. The exquisite song came not from a nightingale but from a special canary that Reich had engineered through a decade of dedicated breeding.1
Duncker’s meeting with Reich was so propitious and so successful that he felt compelled to write a detailed account of how it occurred. The canary had sung from the balcony of Reich’s apartment. Seeing it and hearing Reich’s tale of how he had created it, Hans Duncker was bewitched. He could not believe that Reich, a humble shopkeeper, could have produced such a bird. The scientific implications of Reich’s ingenious canary-nightingale creation were enormous. Reich believed that he had somehow transferred to his canaries the heritable ability to sing a nightingale’s song. But Duncker, a devout Darwinian, knew this couldn’t be true and his own ingenious explanation drew on a subtle partnership of genes and environment that was years ahead of its time.
The nightingale-canary was just the starting point. The two men became firm friends and embarked on a roller-coaster journey of discovery. But it was not the songs of birds that became the main focus of their efforts, but their colour. With Reich’s bird-keeping facilities and Duncker’s scientific knowledge they conducted a full-blown study of the genetics of canary colours. Their results revealed not only that the canary’s colours were controlled in a Mendelian manner, but that it must have taken previous generations of canary fanciers a century or more of selective breeding to transform the canary’s wild ancestor from a dull green bird into the familiar yellow one. Fired by these findings, by great faith in the new field of genetics and subsequently by the generosity of a wealthy benefactor, Duncker devised the audacious and innovative plan to create a brand-new bird of his own: a red canary.
His idea was to pluck the genes from a red siskin – a relative of the canary from South America – insert them into an ordinary yellow canary and turn it red. Duncker half succeeded in this quest and half failed, for a reason that cuts to the very heart of the most important unresolved problem in modern biology. Duncker’s genetic knowledge was unequalled and his logic impeccable, but despite years of trying he was never able to produce a truly red canary. He failed because his belief in genetics was so strong, so all-embracing and, ultimately, so naive. He came within a whisker of success: the canaries Duncker produced were a reddish coppery hue, but he never managed to breed birds of the intense crimson of the red siskin. The problem was that Duncker refused to recognise that colour could be determined by anything other than genes. There’s a dreadful irony here, for when he previously figured out how Reich’s canaries acquired their nightingale song, Duncker explicitly acknowledged the necessity of both an environmental and a genetic input. Had he applied the same reasoning to the birds’ colour, he might have got what he was after. But when it came to feathers he had his heart set on a genetically red bird. It took others in more enlightened times to see beyond Duncker’s genetic horizon.
Our understanding of the relation of genes, species and evolution (which is still, of course, far from complete) started in 1900 with the rediscovery of the ingenious experiments on inheritance in peas carried out during the 1860s by Gregor Mendel in the monastery gardens in Brno. Mendel’s results, though published, lay unnoticed for almost forty years. Once recognised for what they were, they stimulated a tidal wave of new research as well as a torrent of controversy among investigators struggling to make sense of their results. It took two decades of backbiting and character assassination for researchers to sweep away the misunderstandings and to start moving forward on a united front. By the early 1920s the way was clear for a new and exciting phase of genetic endeavour.
Hans Duncker was to birds what Gregor Mendel was to peas. By combining his understanding of inheritance with the hidden knowledge of generations of bird keepers he was able to go one better than either Darwin or Mendel and start to build his own organism – a genetically engineered canary. He also precipitated a fervid worldwide contest among bird keepers to create a red canary.
A genetically engineered animal is one that has had one or more genes from another type of organism added to its genome by man. Today’s technology is so sophisticated that in terms of putting the DNA from one organism inside another it doesn’t matter how similar or dissimilar they are. Molecular biologists have no problem, for example, placing human genes inside a bacterium. But in the 1920s the only way to get the genes from one animal species inside another was by persuading two similar species to copulate, inseminate and fertilise each other. Even this wasn’t sufficient: some of the resulting hybrid offspring had to be fertile. Today’s red canary is a transgenic or genetically modified organism precisely because it contains one or more genes from the red siskin. Creating it involved crossing two species, repeatedly back-crossing their offspring to canaries so as to whittle away generation after generation of the unwanted siskin genes. The aim was to remove everything except the gene or genes that programmed feathers to turn red.
Compared with today’s technology, hybridisation was an extraordinarily blunt instrument. But it worked and the proof in the form of genetically modified canaries exists today at every canary show. Still, the main reason Duncker failed to breed a red canary is easy to see today: genetic knowledge in the 1920s was simplistic. Mendel’s rules were sound building blocks, but subsequent research has revealed an extraordinary number of demons – including imprinting, gene-environment interactions and maternal effects – that can distort Mendel’s tidy ratios.2 Attempting to create a red canary through hybridisation was rather like letting a proverbial monkey loose on a keyboard and expecting Shakespearean sonnets. But the red canary wasn’t created by a mindless monkey. It emerged because by using the genetic knowledge then available together with a bit of luck the colour pioneers eventually found a canary genome that would allow the siskin’s red genes to express themselves. But they needed more than genes to do it.
There was another factor in Duncker’s failure: the Zeitgeist, which in Germany in the 1920s and 1930s was starting to turn horrifyingly ugly. The all-encompassing obsession with genes and genetic heritage that fired Duncker’s quest to achieve a red canary by breeding alone also informed the political and social policies of the Third Reich: breeding, blood and purity of the genes determined everything from colour in a bird to courage in a man. Duncker’s position as a high-school teacher coupled with his success as a geneticist meant that when the Nazis seized power in 1933, they were as keen to appropriate his expertise as he had been to appropriate the red siskin’s genes a decade earlier. Inexorably, Hans Duncker was sucked into the ghastly Nazi machinery that proceeded to tear Europe apart over the succeeding years. Whether he did so willingly remains unclear.
The tale of the red canary is Duncker’s story. But it embraces, too, the personal histories of a handful of others who were driven to transform a sombre little green bird into a flaming red one. This book is also an exploration of the curious interdependency of birds and humans over time and of what it is that drives men like Duncker to pursue a goal as esoteric as a red canary. It is a story that oscillates back and forth between the trivial – the quest for a red canary – and the deadly serious – the political abuse of biology – between good and evil, amateurs and professionals, love and hate and between past and present.
Hans Duncker’s part in creating the red canary is a pivotal one, but his results and the success of his followers represent mere twigs on the ancient tree of bird-keeping tradition. Like most magnificent old trees, it continues to grow but it does so now only slowly. Bird keeping was at its most vigorous in the eighteenth and nineteenth centuries, and those periods of rapid growth and prolific flowering represent a remarkable and fascinating part of history when birds were kept with an almost obsessive zeal. Telling some of this story allows us to better appreciate Hans Duncker’s achievements and to understand why the bird-keeping subculture is the shape it is.
Our relationship with genetics over the last hundred years has been horribly inconsistent. With the initial knowledge gleaned from the rediscovery of Mendel’s work it was easy to elevate genetics to a position of supreme power and see it, as the eugenicists did, as the answer to all biological questions. Theirs was a Utopian vision and their goal was the improvement of the human race through better breeding. After the euphoric days of genetic optimism in the 1920s, events in Germany during the next two decades showed how spectacularly and dreadfully wrong the eugenicists had been. The study of genetics fell into disrepute. It took another thirty years for the subject of how ‘genes’ influence behaviour to re-emerge, albeit cautiously and in a succession of guises: including behavioural ecology in the 1970s, evolutionary psychology in the 1990s and genomics in the last few years. With the current obsession with genes – the human genome project, genetic engineering and transgenic wonders – we are tempted to regard the gene once again as a deity rather than a demon. In our optimistic awe of the power of genes we risk losing sight of the fact that without an environment to operate in genes are all but meaningless.
The Red Canary is the story of how, on their own, genes are not enough. It is a lesson in the history of biology. Understanding the intricate dialogue between nature and nurture – the interactions between genes and the environment – is the single most important biology lesson there is.