Limited Genetic Diversity Preceded Extinction of the Tasmanian Tiger.
I was motivated to look into the fate of this animal by a post here in the science section, this one: Newly Released Rare Video Is The Last Known Footage of a Tasmanian Tiger (Thank you Judi Lynn!)
Apparently the animal underwent two extinction events, the first on the Australian mainland owing to the arrival of the dingo subspecies of the dog, about 5000 years ago, the second extinction - which was a deliberate extinction on behalf of Tasmanian sheep herders - in the early 20th century.
One thing that is often overlooked in near extinction of animals like Cheetahs (which apparently had an earlier near extinction event before the current one), the California Condor, and other animals, is that their surviving populations are weakened by a loss of genetic diversity.
The low genetic diversity of the Tasmanian tiger, a marsupial dog like animal, that survived on Tasmania until the 20th century, was established in a paper published in the open sourced journal PLOS One. The paper is here: Limited Genetic Diversity Preceded Extinction of the Tasmanian Tiger (Brandon R. Menzies1,2*, Marilyn B. Renfree2, , Thomas Heider3, Frieder Mayer4, Thomas B. Hildebrandt1, Andrew J. Pask3, One April 2012 | Volume 7 | Issue 4 | e35433) The authors made their study by obtaining tissue samples of the animal from museums.
An excerpt:
Once found on mainland Australia, a subpopulation of thylacines became isolated on the island of Tasmania after the flooding of Bass Straight approximately 10–13 thousand years ago, and so they avoided the decline and eventual extinction of the mainland population that coincided with the arrival of the dingo, Canis lupus dingo, 5–6 thousand years ago [2]. Based on limited observations and bounty information, the thylacine appeared to be a solitary ambush predator that preferred open woodland habitat. Its former range included the north-western, central, eastern and south-eastern parts of the island of Tasmania, but not the mountainous south-west (Figure 1b) [3], [4].
Far from being appreciated, European settlers deemed the thylacine a threat to the developing colonial sheep industry and it was aggressively targeted for eradication by the government with a £1 bounty paid for every animal killed [3]. Mothers with pouch young or live specimens could be sold to zoos or museums for even greater remuneration. As a result, the remaining population was rapidly exterminated from Tasmania during the bounty period from 1888 to 1912, over which time 2,184 specimens were presented for reward (Figure 1c) [3]. The last known wild thylacine was killed in 1930 and the last known animal died in the Hobart Zoo in Tasmania on the 7th of September 1936 [4].
Currently the other marsupial that survived in Tasmania after extinction in Australia, the Tasmanian Devil, also lacks in genetic diversity, which may be a reason that the animal is facing extinction as a result of a highly transmissible facial cancer.
PLOS One is a very fine open sourced peer reviewed journal with which one can broaden his or her scientific knowledge by reading original papers for free.
Have a nice day.
= new reply since forum marked as read
is David Quammen, whose Song of the Dodo is pretty much an extended essay on that topic. The most current title on his Web page should grab everyone's attention:
The next big and murderous human pandemic, the one that kills us in millions, will be caused by a new disease--new to humans, anyway. The bug that's responsible will be strange, unfamiliar, but it won't come from outer space. Odds are that the killer pathogen--most likely a virus--will spill over into humans from a nonhuman animal.
Spillover is a work of science reporting, history, and travel, tracking this subject around the world. For five years, I shadowed scientists into the field--a rooftop in Bangladesh, a forest in the Congo, a Chinese rat farm, a suburban woodland in Duchess County, New York-and through their high-biosecurity laboratories. I interviewed survivors and gathered stories of the dead. I found surprises in the latest research, alarm among public health officials, and deep concern in the eyes of researchers. I tried hard to deliver the science, the history, the mystery, and the human anguish as page-turning drama.
From what innocent creature, in what remote landscape, will the Next Big One emerge? A rodent in southern China? A monkey in West Africa? A bat in Malaysia that happens to roost above a pig farm, from which hogs are exported to Singapore? In this age of speedy travel between dense human populations, an emerging disease can go global in hours. But where and how will it start? Recent outbreaks offer some guidance, and so I traced the origins of Ebola, Marburg, SARS, avian influenza, Lyme disease, and other bizarre cases of spillover, including the grim, unexpected story of how AIDS began from a single Cameroonian chimpanzee.
The subject raises urgent questions. Are these events independent misfortunes, or linked? Are they merely happening to us, or are we somehow causing them? What can be done? But this book is intended to be more than a work of reportage. It's also the tale of a quest, through time and landscape, for a new understanding of how the world works.
https://www.davidquammen.com/other-books
