Tasmanian tiger's mysterious die-off explained

Until recently, little was known about the mysterious Tasmanian tiger, but new DNA sequences of the dog-like marsupial shed light on the striped creature's surprising family tree and its extinction 73 years ago.

Researchers now believe the Tasmanian tiger, also called the thylacine, went extinct in 1936 after the death of the last known surviving individual at a Tasmanian zoo, and four decades after genetic diversity within the species dropped to a critically dangerous low.

It's thought that the thylacine's path to extinction, however, began much earlier.

www.msnbc.msn.com...

I always thought it was hunting that killed them all, but i guess its because they were all inbreeds. I wonder how many species this is currently affecting?

Around here there is plenty of Human inbreeding.
Seems not to be working here.

reply to post by Grock

it effects cheetah they are genetically bankrupt as a species, thats why they have such a high mortality rate for infants from disease

effectivley they are already extinct they just dont know it yet




[edit on 18/1/09 by noobfun]

reply to post by Grock


That was really interesting - especially

The DNA analysis also determined that, despite the fact that the thylacine resembled a cross between a dog and a tiger, it was a marsupial closely related to striped insect-eaters called numbats, and more distantly to kangaroos and koalas.

I still think hunting would of contributed to their demise - the settlers in Australia were renowned for their wasteful carnage of native Australian wildlife.

reply to post by SINNER901


lol Can you be more specific ?

This is particularly interesting when taken in the context of the development of human beings - in both the "creationist" and "Out of Africa" model.

According to the Out of Africa Model, developed by Chris Stringer and Peter Andrews, modern H. sapiens evolved in Africa 200,000 years ago. Homo sapiens began migrating from Africa between 70,000 – 50,000 years ago and would eventually replace existing hominid species in Europe and Asia. The Out of Africa Model has gained support by recent research using mitochondrial DNA (mtDNA). After analysing genealogy trees constructed using 133 types of mtDNA, they concluded that all were descended from a woman from Africa, dubbed Mitochondrial Eve.

Although the surviving bloodline appears to originate from "Eve", surely there must have been "interbreeding" with another bloodline or we would have had severe inbreeding issues?

Even breeding cousins, legal in many countries, appear to exacerbate existing genetic conditions and here we are talking about a single woman and her children as the source of human life. Surely not without some form of divergence added via breeding with other hominids?

Although the bloodline traces back to a single female, it would be ridiculous to think that many females were not present at the time (i.e. she didn't just evolve by herself). If this is the case, why haven't the other bloodlines survived?

Perhaps they got killed by the flood?

or perhaps The homo sapien species almost became extinct itself in Northern Africa, and somehow they survived. Via a monolith, environmental adaptation, or perhaps Mr Lizard helped them along.

www.bbc.co.uk...

Originally posted by SugarCube
This is particularly interesting when taken in the context of the development of human beings - in both the "creationist" and "Out of Africa" model.

not really, it supports the out of africa model and what we know about the spread of early homosapiens

Although the surviving bloodline appears to originate from "Eve", surely there must have been "interbreeding" with another bloodline or we would have had severe inbreeding issues?

they dont all come from 1 woman in a garden of eden style eve

the trait of eve was passed on her kids which was passed to thiers so on and so on, and as the lines crossed across those without the trait they inherited them so it has spread through the population

so yes were all technically decended from eve but it was her daughters (im not talking direct but many generations down the line) breeding with other genetic groups that stopped us bieng extra's in the hills have eyes

Even breeding cousins, legal in many countries, appear to exacerbate existing genetic conditions and here we are talking about a single woman and her children as the source of human life. Surely not without some form of divergence added via breeding with other hominids?

nope becasue her grand daughters and great granddaughter (so on and so on) breed with men not descended directly from her so the trait spread but the genetics got mixed up

we have gone through periods of very low populations leading to inbreeding but becasue humans have a habit of A) surviving B)moving to new areas we always had those periods of seperation for our genetics to diversify within those seperate comunities and then later become re-merged

which is why sickle cell disease is an african trait primarily passed on within or between local villages but not spread wide enough to essentially leave africa, but now(couple of hundred years) were all happily humping and recombining external genetic groups back into those population genetics sickle cell disease is decreasing

we still have a vast array of genetic defects and syndromes we carry around in our dna which shows we have gone through bottle neck situations a couple of times with a few thousand making up the breeding population, but its our spreading populations and then recombining that keep us for the most part working properly

we suffer the same as chimps they have gone through similar bottle necks and we share a bunch of genetic defects from inbreeding carried from our common ancestor and earlier

www.newscientist.com...

*Edit**

dont forget Y chromosone Adam too but they are about 80,000 years seperated


covers human evolution, the last 2 minutes cover Mdna eve


covers human migration and Y-chromosone adam

[edit on 18/1/09 by noobfun]

That reminds me, i recently heard on the news that someone somewhere was planning on trying to bring back the thylocine using some sort of cloning, anyone with info on that? is it even possible?

It's possible, as is anything else, just really improbable.

this entire " explaination " sounds to me like dishonest apologetica

the reason genetic diverity plummets in species is because blood lines are removed [ zoo capives ] or shot by hunters

it is human interference that precipitated the " dangerous inbreeding " of wild stocks

as the plight of the cheetah in africa has already been mentioned - it serves my point to note theat scientists ate atttempting to ` deepen the geene pool ` in wild african cheetahs [ now reduced to < 50 wild bloodlines in the entire continent ] by re introducing captive bred cheetahs

now maybe if these bloodlines had not been removed from the wild in the first place the problem would not have arisen

in the case of cheetah the bottle neck appears to have happened around 10,000 years ago

the inbreeding has lead to massivley reducred spermatazoa counts and high infant mortality rates making it difficult to recover sufficient numbers for breeing isolations and reintergrations to happen

even the captive populations are as bankrupt as south african cheetah as thats where the majority came from. A 1987 study showed east african cheetah are more diverse in genetics .14 as opposed to the 0.0004 displayed by south african cheetah but the eastern population is tiny so care has to be taken with inter breeding the two groups so the east african population dont get swamped and loose thier genetic variation

a study was carried out using skin grafts from 12 unrelated and 2 related cheetah(captive decended from south african cats) and a domestic cat, the domestic cat rejected its grafts in under 2 weeks (7-14 days is average for skin grafts from other domestic cats too) and showed rapid rejection taking place over a couple of days

of the cheetah only 4 showed slow rejection and the rest accepted the graft without trouble

compare that to humans even in closley related people(say brother and sister) the grafts will always be rejected(same as the domestic cat) which is why organ transplant means a life time of medication to prevent rejection

theres some hope for them other severly inbreed species in breeding programs when correctley managed to avoid close breeding have been able to rebuild a semi viable gene pool but will still be in danger of virulant strains of disease wiping out almost entire population groups for a long time and northern elephant seals had almost as low genetics but since bieng protected have started to massivley repopulate (seems the inbreeding didnt effect its sperm count and infant mortality rate in the same way)

i think a smiliar thing may have happened with thylacines they suffered a bottle neck which critically lowered genetic diversity then us storming in changing the habitat and hunting them with extreme prejudice was the final death blow

there are still several thylacene reports each years, but like bigfoot (or blobsquatch as the picture evidence usually shows it)the evidence is sketchy and usually blurred video/photos but we deffinatley know thylacines existed so it may be theres still a few around with an extreme dislike and rust of man and staying the hell away as best they can, but thats probabily just wishful thinking

www.bioweb.uncc.edu... 1980's study of south african cheetah diversity or lack of

www.catsg.org... small article on the 87 genetic research on east african genetic variation

[edit on 20/1/09 by noobfun]