The dodo, a flightless bird native to the island of Mauritius, holds an iconic place in history as a symbol of extinction. Its disappearance centuries ago has long served as a cautionary tale about humanity’s impact on nature. However, recent advancements in genetic science have sparked a new conversation: could the dodo, or at least a close genetic approximation, ever walk the Earth again through the emerging concept of “de-extinction”?
The Dodo’s Disappearance
The dodo inhabited Mauritius, an island in the Indian Ocean, evolving in an environment without natural predators. This led to its flightlessness and tameness, making it unafraid of humans. Portuguese sailors first encountered these birds around 1507, with documented mentions appearing by 1598 from Dutch explorers.
The arrival of humans on Mauritius marked the beginning of the dodo’s rapid decline. Sailors hunted the birds for food. Introduced invasive species like rats, pigs, and macaques, brought by ships, preyed on dodo eggs and competed for resources. Deforestation for plantations also destroyed their habitat. The last known dodo sighting occurred in 1662, and the species is estimated to have become completely extinct by the 1690s, less than a century after its first documentation.
The Science of De-Extinction
Bringing back an extinct species like the dodo relies on sophisticated scientific principles, primarily genetic engineering and cloning. The first step involves obtaining viable DNA from preserved dodo specimens, such as bones or museum samples. While DNA degrades over time, the dodo’s relatively recent extinction compared to, for example, dinosaurs, means enough genetic material may remain for sequencing.
Once dodo DNA is acquired, its entire genome is sequenced. Scientists then use genetic engineering techniques, notably CRISPR/Cas9, to modify the genome of a closely related living species. The Nicobar pigeon, a close relative of the dodo, is a prime candidate for this genetic modification. The goal is to edit the pigeon’s DNA to incorporate dodo characteristics, effectively creating a hybrid resembling the extinct bird.
Following successful genetic modification, the challenge shifts to bringing the engineered embryo to term. Traditional cloning methods face significant hurdles in birds due to the structure of avian eggs. Instead, the plan involves creating dodo gametes (reproductive cells) and then using a surrogate mother species, such as a chicken or a Nicobar pigeon, to carry the engineered embryo. This process aims to create a living replica, though not an exact genetic duplicate of the original dodo.
Navigating the Hurdles
Despite scientific advancements, de-extinction projects, particularly for the dodo, face substantial obstacles across multiple domains. Obtaining high-quality, complete dodo DNA remains a significant scientific hurdle. While fragments have been sequenced, assembling a flawless dodo genome from degraded ancient DNA is a complex task.
Finding a suitable surrogate species and successfully carrying an engineered embryo to term is another major scientific obstacle. Even with alternative methods, the success rate of such pregnancies is uncertain.
Beyond the laboratory, ecological challenges loom large. The dodo’s original habitat in Mauritius has been drastically altered over centuries, with only about 4.4% of its original habitats remaining. The altered ecosystem of Mauritius still harbors invasive species like macaques and rats. Reintroducing a resurrected dodo into this changed environment raises questions about its ability to survive and thrive, and its potential impact on existing species.
There are also ethical considerations surrounding de-extinction, including debates about “playing God” and the allocation of resources. Some argue that significant funding for de-extinction projects could be better spent on conserving currently endangered species, such as the pink pigeon of Mauritius.
Implications of Revival
The successful de-extinction of the dodo, or any species, would have significant implications for conservation science and humanity’s relationship with the natural world. It would demonstrate humanity’s capacity to reverse, at least in part, past ecological damage. Proponents suggest that the knowledge and tools developed through de-extinction efforts could benefit the conservation of currently endangered species.
Bringing back a species like the dodo could also spark public interest in conservation, raising awareness and bringing the topic to the forefront of cultural discourse. However, concerns persist that de-extinction might divert attention and resources from protecting existing biodiversity.
The purpose of de-extinction continues to be debated: is it to correct historical wrongs, advance scientific understanding, or offer new solutions to the biodiversity crisis? Critics also raise questions about the quality of life for de-extinct animals, particularly if they lack natural behaviors or suitable habitats. The possibility of de-extinct species wreaking ecological havoc if introduced into fragile ecosystems is also a concern.