The Tasmanian Tiger: The Long Journey to Resurrect an Icon
The Tasmanian Tiger is one of the most famous extinct animals. Also known as the thylacine, it survived well into the modern era and we even have film footage of a living example.
Sadly this footage was of the last tiger, which died in captivity on the 7th September 1936 in Hobart Zoo on the island of Tasmania. But perhaps this beautiful creature is not lost forever, according to a new press release from Colossal Biosciences.
The company has actually announced multiple breakthroughs, all of which they believe brings the day closer when this extinct marsupial can be brought back to life. The key announcement is an almost entirely complete thylacine genome, with only 45 gaps in the sequencing which it is hoped will be closed in the near future.
The key to this success was the quality of the material used to extract the genetic information. Beth Shapiro, chief science officer for Colossal, explained: “The thylacine samples used for our new reference genome are among the best preserved ancient specimens my team has worked with.”
The team estimate the genetic information to be >99.9% accurate, which they consider exceptional as most extinct species do not contain anything like as much DNA. Most preserved bodies of extinct animals are far more degraded, making the extraction of DNA far harder.
Even more impressively, the team have been able to extract RNA sequences from preserved tissue. RNA is far less stable than DNA and therefore it is extremely rare to have such information, but in this case it was preserved almost by accident.
The RNA strands were taken from the head of a thylacine which was skinned and preserved in ethanol. This was, luckily, an almost perfect environment to prevent the head from degrading.
RNA is so important because it details the genetic function of individual tissues throughout an organism. DNA is a standard code embedded in every cell, but RNA is different in different places.
This new information will therefore be able to identify the genes the thylacine employed for taste, smell, vision and brain function. This will be particularly because of the unusual skull formation observed in these creatures.
Tasmanian tigers had exceptionally articulated lower jaws, able to open them extremely wide. Other features are shared with extant canids such as wolves, and it is hoped that the research will allow us to understand how these skulls evolved, and which parts of the genome are responsible for these features.
So far, so fascinating but none of this actually brings the tiger back. That is where the other aspect of the team’s focus lies: with inducing ovulation in a fat tailed dunnart.
The dunnart is a marsupial identified as a candidate through which the tiger can be recovered. The team have successfully fertilized the eggs produced through the procedure, and although none made it to term it is seen as a major breakthrough.
And once all these disparate strings are pulled together, we just might once again see the Tasmanian tiger in the flesh.
Header Image: The last known Tasmanian tiger in captivity. It is hoped that this new research will be able to resurrect the extinct marsupial. Source: Unknown Author / Public Domain.
