Tinkering with Extinction


By Tanya Silverman

Photo courtesy of frankieleon.

Extinct means dead, gone forever. Or does it? A number of scientists have joined forces to attempt to reverse the extinction of several bygone species.

Environmentalists and conservation biologists involved in the de-extinction movement aim to revitalize extinct animals like California condors, carrier pigeons, European aurochs, and Tasmanian tigers, plus plants like American chestnut trees. One de-extinction project is Revive & Restore, which is a section of the California non-profit Long-Now Foundation. Its scientists study the DNA of extinct creatures with the hopes of ultimately bringing them back to life and introducing them into the wild.

The de-extinction movement harbors an ethical element. Members of the human race feel guilty that our species has caused the wipeout of others. In fact, it’s speculated that humans may be responsible for causing the Sixth Extinction, when massive amounts of species will die off largely due to factors like pollution and climate change.

So far, the only case of realized animal de-extinction occurred in 2009, when a goat birthed a cloned Pyrenean ibex, a species which died out in 2000. The feat was a short-lived one, though, as the infant ibex died after just a few minutes due to breathing problems.

More recently, scientists were successfully able to map the genome of a wooly mammoth. The Washington Post reports that some mammoth “revivalists” perceive the mapping as a potential blueprint they could use to tinker with existing elephant DNA and engineer mammoth-like mammals. However, there is an ethical debate over whether it’s right to subject elephants to become surrogate mothers for species that went extinct 4,000 years ago.

Meanwhile, a completely separate team of scientists is focused on animal species experiments dating back way before any humans (or any of the aforementioned species) inhabited the Earth. They took things back to before the Fifth Extinction, 65 or 66 million years ago, when an asteroid’s impact may have wiped out the majority of life.

Indeed, these researchers succeeded in engineering an embryonic dino-chicken. They did so by altering the molecular development of the avian embryos’ beaks by blocking proteins. So, instead of growing beaks, these embryonic chickens developed snouts that resembled those of feathered, bird-like dinosaurs such as the Velociraptor and Archaeopteryx.

Photo courtesy of ficusdesk.

“Not only did the beak transform, but the palatine at the roof of the mouth effectively also transformed into a more ancestral shape,” lead researcher, Bhart-Anjan Bhullar, affirms with BTR.

Bhullar is a paleontologist and developmental biologist at the University of Chicago and Yale. He conducted the study with his doctoral advisor, Arkhat Abzhanov, a Harvard University developmental biologist, along with a team of several researchers.

The goal of manipulating the dino-chicken was for the purposes of studying bird evolution. Fossil records show that birds developed beaks from the premexillae, which Bhullar describes as “tiny bones at the tip of the snout.”

“When you look at birds, it seems like they have very long snouts, but that’s actually an illusion,” he explains. Avian species, he continues, actually have a very short face, except for the premexillae. This “tiny ancestral pair of bones,” he illustrates, grew enormously large and fused “to each other to form this giant pointed structure which is the beak.”

Studying the beak is vital to understanding evolution in birds; Bhullar references Charles Darwin’s work with finches in the Galapagos. The researcher also mentions that there are about three times as many species of birds as mammalians. Birds vary greatly in terms of beak composition–think of the differences between humming birds, toucans, flamingos, parrots, and eagles.

“We were very happy to see we advanced the knowledge of this evolutionary transition,” Bhullar states.

Now, for readers who’ve been speculating that they will soon be able to adopt their own dino-chicken pet–right in the nick of time for the release of Jurassic World–don’t get your hopes up. Bhullar says that there is no intention or reason to hatch the embryos.

“One needs to go through all sorts of ethical procedures, and rightly so, to hatch anything that’s been manipulated,” reasons Bhullar.

He says, though, that these chickens may have done just fine. He brings up his recent visit to The Field Museum in Chicago where he viewed a number of pigeons that humans bred through artificial selection, noting that the physical changes he witnessed there were far more extreme than what he and the other researchers had completed with embryonic chickens.

As for future research, Bhullar wants to delve deeper into discovering “the history and the mechanisms behind major transitions in the history of life.” He says it’s fortunate that birds are easy to study in their embryonic state, and that he wants to investigate “the origin of the big brain, the big eyes, the wings,” and other gaps in evolutionary knowledge.