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from the their-genes-should-have-worked-out-more dept.
Tasmanian tigers were suffering from poor genetic diversity prior to being hunted to extinction by humans:
Australian scientists sequenced the genome of the native marsupial, also known as the thylacine. It showed the species, alive until 1936, would have struggled to survive even without human contact. The research also provides further insights into the marsupial's unique appearance.
"Even if we hadn't hunted it to extinction, our analysis showed that the thylacine was in very poor [genetic] health," said lead researcher Dr Andrew Pask, from the University of Melbourne. "The population today would be very susceptible to diseases, and would not be very healthy."
He said problems with genetic diversity could be traced back as far as 70,000 years ago, when the population is thought to have suffered due to a climatic event.
The researchers sequenced the genome from a 106-year-old specimen held by Museums Victoria. They said their study, published in the journal Nature Ecology and Evolution, is one of the most complete genetic blueprints of an extinct species.
Genome of the Tasmanian tiger provides insights into the evolution and demography of an extinct marsupial carnivore (open, DOI: 10.1038/s41559-017-0417-y) (DX)
Related: Huge Population and Lack of Genetic Diversity Killed Off the Passenger Pigeon
(Score: 2) by Immerman on Tuesday December 12 2017, @07:48PM (4 children)
Not quite. The "robustness" that's in question is diversity. The mere fact that a species has been driven close enough to extinction that it has to make a comeback, will likely deprive it of much of that diversity going forward. Given enough time to prosper, mutation will eventually reintroduce diversity, but that takes many tens of thousands of years. Cheetahs experienced such a bottleneck about 10,000 years ago, at the end of the last ice age, and still have very little diversity.
Something happened to the Thylacines about 70k years ago that similarly bottlenecked the population - the fact that humans arrived in approximately the same time period, coupled with the fact that megafauna extinctions have followed humans wherever we've gone, suggests that humans might be what happened to them, or at least prevented them from prospering during their recovery.
However, humans also seem to have gone through a bottleneck at about the same time - so it is quite possible that some climate changes were responsible. If that were the case though, you would expect to see several species that dwindled or went extinct at about the same time - predators rarely suffer so long as prey is plentiful.
(Score: 2) by Grishnakh on Tuesday December 12 2017, @09:34PM (1 child)
Genetically speaking, humans are also extremely non-diverse. By all rights, we should be going extinct. Unfortunately, we don't have any real predators.
(Score: 2) by takyon on Tuesday December 12 2017, @09:38PM
Anti-humanist spotted.
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 2) by frojack on Wednesday December 13 2017, @05:29AM (1 child)
This is the second genetic diversity responsible for extinction article in as many months. Both exonerating human actions, if not explicitly then by inference. The passenger pidgon was the other.
Genetic diversity as an Extinction mechanism is a relatively new theory, one that some people are trying to push very hard lately for some reason.
I'm not sure I buy the assessment of lack of diversity or the perceived death sentence it is made out to be. Alligators and crocodiles have low diversity as well as limited ranges. They are among the longest extant species around.
No, you are mistaken. I've always had this sig.
(Score: 2) by Immerman on Wednesday December 13 2017, @02:50PM
I've got to agree it's not a death sentence, just an increased vulnerability. The thylacines managed to hang on 70,000 years after their genetic bottleneck, until Europeans came along and hunted them to extinction. For that matter humans bottlenecked at about the same time, with some estimates putting the global population at only ~2000 individuals.
It also strikes me that while diversity is a big advantage against disease, and a longer-term one in terms of evolutionary adaptation, both thylacines and pigeons were hunted to extinction over a very short period by the most efficient predator on the planet. No amount of diversity is likely to help against that.