“Can we bring animals back from extinction?” In a panel discussion on this topic organised recently by the Royal Society, evolutionary biologist Beth Shapiro mentioned that if there were an animal she would like to bring back from extinction, it was the dodo. This follows on the fact that researchers at her lab at the University of California, Santa Cruz have succeeded in isolating the entire genome of the dodo.
What is the dodo, and why is it so interesting?
The dodo is a bird that lived in the Mauritius region and was last spotted 350 years back, in 1662. Since then it has become extinct. It would not be exaggerating to say that it is the very symbol of extinction. The phrase “dead as a dodo” is common in English to refer to something totally dead. The form of the bird has been revived from old drawings and the closest resemblance is in an Indian Mughal painting rediscovered in the Hermitage Museum in St Petersburg. In the painting it is slimmer and browner than in other descriptions. It is believed to be a more accurate depiction because it is pictured along with other birds which can be easily identified. The painting is by Mughal painter Ustad Mansur, probably commissioned by Emperor Jahangir who was famous for getting flora and fauna documented in paintings.
So, bringing the dodo alive would be the ultimate story of de-extinction.
How does the dodo look?
A species endemic to the island of Mauritius, the dodo is believed to be about 1 metre tall, flightless and weighed between 10 and 18 kilograms. Its real appearance is known only from paintings and drawings which vary a lot.
What animal is its closest living relative and how do we know that?
Beth Shapiro’s lab has sequenced the complete genome of the dodo, in work that is as yet unpublished, and she says that the closest living relative of the dodo is the Nicobar pigeon.
How does one recreate the full genome of an ancient, dead animal?
You need a specimen of the animal that has not been fossilized over the ages. Icy places like permafrost may contain remains of living beings in such a preserved form.
A small piece about the size of a finger-nail is taken from these specimens, and broken into small pieces. In an absolutely uncontaminated state, this is added to a PCR kit which multiplies the genome and makes many, many copies. From these fragments, the entire genome is pieced together, comparing it to genomes of other, living close relatives.
First the researchers in Shapiro’s team tried to do this from a piece taken from a specimen at Oxford. But it was not nearly large enough. Later they found a specimen in Denmark from which they were able to sequence the entire Genome.
Can the genome be used to resurrect an animal, In particular the dodo?
Beth Shapiro explained in the discussion that the known way of doing this would be to first stick in parts of the extinct animal’s genome into a framework provided by its close relative. For example, by inserting the mammoth genome into the elephant’s and construct a cell that contained sufficient amount of mammoth genome in it and then to clone it like Dolly the sheep. But while this process has been somewhat understood in the case of mammals, a new process has to be worked out for birds. “There are different groups that are working on this, and I have no doubt that we’ll get there, but this is a hurdle we face with birds,” she said.
