Imagine a world without the dog – often called man’s best friend. A world also without cows, pigs or sheep. If our ancestors had not domesticated many animals and plants a few thousand years ago, there would be no fields of grain, rapeseed or cotton. All animals would be wild. Humans would hunt, fish and gather plants in nature to put food on the table. In short, virtually every aspect of our lives would be radically affected if the phenomenon of domestication were to be deleted from the history of the Earth.
Useful tool for research
For Dominic Wright, professor of genetics, domestication is also a useful tool in research into how genes affect traits such as behaviour and appearance. He finds it interesting how domestication has been able to change animals to such an extent as certain desirable properties have been enhanced when humans have controlled selection. The difference between a wild and a domesticated variety within a species is often greater than the difference between different species.
“We’re trying to find genes that control different properties. If we look at a property such as height in humans, it doesn’t vary that much. The tallest ones are perhaps double the height of the shortest ones, at most. But domestication has driven the change of certain properties so effectively that in the case of chickens, a modern broiler weighs around seven times as much as its wild relative, the red junglefowl. The large variation makes it easier for us to find genes that affect a specific property.”
From tame to wild?
By comparing domesticated chickens and junglefowl, Dominic Wright and his colleagues have mapped genes in chickens that determine things such as the size of the comb, fear of humans and parts of the brain affected by domestication.
He has now received funding from the independent organisation Revive & Restore, which promotes the use of biotechnologies to preserve endangered species.
“This is a fantastic opportunity that I’m very excited about. We will test whether we can depart from domesticated chickens and change up to about 30 genes to see if this actually changes behaviour and if we end up with a wild bird.”
He has joined force with an American research group, which will make the genetic changes selected by the LiU researchers. If this works out well, they will be able to prove that it is possible to change an animal to the extent that it would go from domesticated to wild.
“If we succeed, this would be the world’s most genetically modified animal. The reason we want to test whether this principle works is that we could then try to recreate the passenger pigeon by genetically modifying its closest living relative,” says Dominic Wright.
Recreate extinct pigeon?
If you haven’t heard of the passenger pigeon, it’s no wonder. The species has not been around for over a hundred years The last known specimen, Martha, died in captivity in a zoo in 1914. But the passenger pigeon was once the most common bird species in North America, before it became extinct due to hunting and habitat loss.
The possibility to recreate extinct species has been tantalizing people’s imagination for a long time. But with methods such as the CRISPR genetic scissors and similar advances transforming this idea from science fiction to being within reach, this ambition raises many questions.
The debate raises arguments about humanity’s role in, and responsibility for, the ecosystems of which we are a part. Proponents argue that we have a moral obligation to try to undo some of the harm caused by humanity. Perhaps it is possible to regain balance in some ecosystems, where invasive species cause problems because humans eradicated the predators that could have kept these populations in check. The technologies developed for these purposes may also have the potential to revolutionise other areas, such as health care or agriculture.
Opponents emphasise that it is difficult, if not impossible, to predict the consequences. The same technologies can be abused by state or individual actors and cause more harm than good. They also point out that reintroduction of species can upset the balance of existing ecosystems in dangerous ways. Resources and commitment should be directed toward preserving endangered species that still exist, they say.
According to Dominic Wright, Revive & Restore stresses that genetic engineering should not be seen as a substitute for other efforts, but as a complement. He has a similar view:
“I don’t think humanity is going to start recreating a lot of species that we have eradicated. But genetic modification can be an additional effort. More genetic variation could be introduced in a very small, critically endangered population and help make it more viable. It could be a very powerful tool, but not to the extent that it replaces actual conservation efforts.”
Photographer: Charlotte Perhammar