Genes extracted from the now extinct Tasmanian tiger (thylacine) have been inserted into a mouse, where they not only were synthesized but also showed biological functionality. This is the first time a functional response has been generated from DNA from an extinct species, and the results show that the protein, thylacine Col2a1, serves a similar function in the transgenic mouse as it did in the original species. This study was published in the open access international journal PLoS ONE on May 19, 2008.

Thylacinus cynocephalus, the Tasmanian tiger, was a large carnivorous marsupial which, by the time European settlement of Australia occurred, kept its primary habitat on the island of Tasmania, with its close relative the Tasmanian devil. The tiger is believed to have been hunted to extinction in the twentieth century, and the last confirmed Tasmanian tiger died in captivity in the Hobart Zoo in 1936. Thankfully, several museum collections preserved some young and adult tissues in alcohol, giving us access to the DNA sequences of these animals. The protein Col2a1 is involved in the production of part of the collagen protein polymer. As a result, it has an important role in the development of cartilage and bone.

The leader of this research, Andrew Pask, RD Wright Fellow at the University of Melbourne’s Department of Zoology, said, pointing out the novelty of this research: “This is the first time that DNA from an extinct species has been used to induce a functional response in another living organism.” He continued, commenting on the ecological implications of such losses: “As more and more species of animals become extinct, we are continuing to lose critical knowledge of gene function and their potential.”

Functional proteins are more useful than simple sequences for these genes, says Pask: “Up until now we have only been able to examine gene sequences from extinct animals. This research was developed to go one step further to examine extinct gene function in a whole organism.” Professor Richard Behringer, Deputy Head of the Department of Molecular Genetics, M.D. Anderson Cancer Center, at the University of Texas, and author on the same paper, points out the many directions further research can take. “This research has enormous potential for many applications including the development of new biomedicines and gaining a better understanding of the biology of extinct animals.”

This research team studied thylacine specimens from Museum Victoria in Melbourne Australia in order to examine the functionality of its genome. DNA was isolated from 100 year old ethanol fixed specimens — once it was authenticated by species, the material was inserted into mouse embryos and examined functionally. It was found that the thylacine DNA expressed and showed function in the developing mouse cartilage.

These results have great implications on the study and application of genetic biodiversity. “At a time when extinction rates are increasing at an alarming rate, especially of mammals, this research discovery is critical,” says Professor Marilyn Renfree, Federation Fellow and Laureate Professor in the University of Melbourne’s Department of Zoology. The senior author on the paper continued, “For those species that have already become extinct, our method shows that access to their genetic biodiversity may not be completely lost.”

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PLoS ONE is the first journal of primary research from all areas of science to employ both pre- and post-publication peer review to maximize the impact of every report it publishes. PLoS ONE is published by the Public Library of Science (PLoS), the open-access publisher whose goal is to make the world’s scientific and medical literature a public resource.

Resurrection of DNA Function In Vivo from an Extinct Genome.
Pask AJ, Behringer RR, Renfree MB
PLoS ONE 3(5): e2240.
doi:10.1371/journal.pone.0002240
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Written by Anna Sophia McKenney