Tasmanian Times

The individual has always had to struggle to keep from being overwhelmed by the tribe. If you try it, you will be lonely often, and sometimes frightened. No price is too high for the privilege of owning yourself. ~ Friedrich Nietzsche

The individual has always had to struggle to keep from being overwhelmed by the tribe. If you try it, you will be lonely often, and sometimes frightened. No price is too high for the privilege of owning yourself. ~ Friedrich Nietzsche

David Obendorf

Fox scat test accuracy doubt

TWO-YEAR-OLD scats will have to be retested for fox DNA after a false-negative result raised doubts about the accuracy of the original tests.

The Fox Eradication Taskforce yesterday revealed a scat collected in the North-West in February 2010 had been confirmed as being from a fox.

The scat was collected during an investigation of a reported sighting of a fox by a member of the public.

Trained detector dogs reacted to the scat, but analysis by the University of Canberra’s Institute for Applied Ecology found the scat could not have come from a mammal.

But a retest was ordered using an enhanced DNA analysis subsequently developed which finally confirmed the presence of fox DNA in April.

The taskforce did not release the result until now because of the “potential implications” of the development in the testing procedure.

In an email sent to subscribers, the taskforce outlined plans to retest two groups of scats collected between 2008 and 2010.

Of the 20 per cent of scats found to have no mammalian DNA, those found in non-core habitat and collected during post-bait monitoring will be retested.

Yesterday, the department was unable to say how many scats would be retested in total and how much it would cost.

Sceptics have slammed the state government’s eradication efforts, which have been allocated $70 million over 10 years in 2008-09, as minimal evidence of a fox presence has been discovered.

Fox scat test accuracy doubt in The Examiner HERE

On Tasmanian Times: Dr David Obendorf, HERE

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15 Comments

15 Comments

  1. David Obendorf

    August 22, 2011 at 6:02 pm

    If they had the scientific integrity that could prove that the half dozen or so microsatellite markers they use for genotyping the fox scats recovered in Tasmania they will publish the data in a peer-reviewed molecular biology journal with the complete nucleotide sequences of those microsatellites for each scat or physical evidence sample.

    So far they have used two molecular genetics labs at University of Canberra and University of Westerna Australia to replicate the amplification of these sequences in ~16 fox scats from Tasmania but they have not published the sequences in detail and have yet to demonstrate any repetition of the same sequence in any DNA fox-positive scats or any of the physical evidence (skull, blood or dead bodies) collected in Tasmania since the programs inception in 2001.

    The 11 or so ‘false negative’ scats that they may now wish to retest will require a very high degree precision to ensure the specific genetic fingerprint in each sample is authentic and backed up by verifiable quality assurance.

  2. Ian Rist

    August 22, 2011 at 2:42 pm

    I am firmly of the opinion that the best testing to get to the bottom of all this foxy business would be lie detector tests.
    Be prepared for the Polygraph to go off the scale many, many times.

  3. Ian Rist

    August 20, 2011 at 4:21 pm

    Nah David it will be to match up different scats from the same fox…always has been their Achilles heel.
    Then again the scat saga has had some twists and turns, remember when we were alerted from within DPIPWE that the famous scat dogs couldn’t find fox scats unless the scats were in plastic film containers…problem was the dogs were equally as good at finding the plastic capsules minus the scats!
    Fuji, Kodak and Agfa…woof, woof now give me a Good-O.

  4. David Obendorf

    August 20, 2011 at 1:30 pm

    Mr Rist, we know for a fact that the Tasmanian Fox Taskforce advertised for fox hunters in Australia to do precisely what you have detailed in comment #9 – namely retrieve faeces from the rectums of shot wild foxes so that their last crap could be sent to Tasmania. [Tasmanian Times readers who are interested in this topic might like to examine the back stories that revealed this activity, including the advertisement published in a hunter magazine.]

    But why – in 2011 – is the Fox Program now asking for a hand-full of old DNA-test negative scats, collected up to three years ago, to be retested?

    I ask again, is the Fox Program going to go back to those areas where retested scats came from and apply another dose of ‘eradication’ 1080-baiting?

  5. Philip Lowe

    August 20, 2011 at 11:02 am

    Same old,same old shit?

  6. William Boeder

    August 20, 2011 at 1:33 am

    Pleased I am that these non-fox eradicator dudes are not in the public sector, imagine the amount of strife and bedlam this lot could create?
    For all those that think we have foxes in Tasmania, I have only one thing to say, it all started off as Bullscat and has always been nought but a great load of “Bullscat!”

  7. Ian Rist

    August 20, 2011 at 12:13 am

    David single scats in the form of the last scat removed from a dead foxes rectum aren’t going to multiply no matter what test they do because dead foxes that have had their last scat squeezed out over the anal gland simply don’t crap again.
    From my colleagues on the mainland I understand the sequence must be when skinning the fox the last scat is squeezed out from inside of the abdominal cavity.

  8. David Obendorf

    August 19, 2011 at 8:25 pm

    It is a rather odd article from Rosemary on ‘false positive’ fox scats but it didn’t get the crux of it!

    Just how are these old scats going to be ‘retested’?

    Did the testing labs keep some for these negative scats freeze-dried in case of just such an eventuality? Normally the intestinal cells containing the host-DNA is washed from the surface of the scat before the DNA is amplified and sequenced.

    Perhaps it would have been precautionary to have some independent oversight of the scat DNA test as has been suggested previously by Dr Clive Marks.

    If this retest now turns up loads of fox-scat clusters, what then?

    Is the Fox Program going to go back to those areas where retested scats came from another and apply another dose of ‘eradication’ 1080-baiting?

  9. Karl Stevens

    August 19, 2011 at 3:37 am

    “Tasmania – Excellence In Fox Scat Identification” The Garvan Institute can spend years searching for a cancer cure but here we are world leaders in fox scat monitoring and analysis. David Obendorf raises the question of ‘monocrappers’ but could it simply be ‘fox constipation’? We could establish world dominance in the field by developing fox laxatives. By carefully disguising these laxatives we can get the foxes moving thereby proving their existence conclusively. After we establish weather they exist or not we can then export the fox laxatives to other countries that have also lost the plot.

  10. Ian Rist

    August 18, 2011 at 1:03 pm

    I wonder if Australia Post could do some testing as they go either way?

  11. David Obendorf

    August 18, 2011 at 3:58 am

    An expensive forensic game this fox scat business. I look forward to Dr Clive Marks or Alexander contributing a comment to this article.

    Of the 56 or 57 DNA-fox positive poos found so far since 2004 in Tasmania, the current tally is that 15 different foxes produced one poo each (the other poos found were not able to be genotyped). In addition so far there is no match of any poos with the other phyisical fox evidence found in Tasmania (e.g. the fox that was claimed to have met its demise on Glen Esk Road on 1 August 2006 or a fox skull found near Interlaken in late 2008 or early 2009).

    So far the data would suggest that our foxes are monocrappers; i.e. only a single poo per Tasmanian fox. I once asked why if the Program had an “excellent” fox sighting (i.e. Kenilworth fox in 2008) and they got a fox-poo detector dog to find a fox poo in the vicinity; why they didn’t continue systematically looking for more fox poos in the same area. Now if all those poos had the same fox genotype then the Program would have something to “Tally-ho” about.

    Even our fabled ‘Bruny Island fox’ seems to have only passed one faecal motion on its sojourn through that part of Tasmania.

    “We can confirm that DNA from the Interlaken skull does not carry the exact same genotype as any scat genotype and so that fox cannot be responsible for leaving any of the scats genotyped to date”. [Reference: Anna MacDonald and Stephen Sarre (2011) – Genetic species identification and microsatellite genotyping of a putative skull and fox-positive scats collected in Tasmania. Report of the Institute of Applied Ecology & the Invasive Animals CRC, May 2001]

  12. Garry Stannus

    August 17, 2011 at 10:03 pm

    The bottom line from the task-force seems to be saying:

    ‘Actually, more of the tested scats were actually from foxes than previous results indicated’.

    The politics and polemics aside, what says science?

  13. William Boeder

    August 17, 2011 at 5:45 pm

    Only in Tasmania will you find that the faeces of animals (introduced Fox poo,) is being subjected to a post-mortem for a far more defining probe into its faecalness.
    Could the brains-trust individual that has come up with this expensive diversionary tactic have his/her name broadcast to the fascinatingly bemused public?
    I myself am quivering with excitement that this rather equivacatory yet obviously an innovative most brilliant theory, has become the major compelling force to the rematching of poo to poo?

    I believe the same equivacatory yet innovative most brilliant theory will sit along-side that of the State government approved notion of selling bottled sunshine en-masse to the people of Tasmania?

  14. Ian Rist

    August 17, 2011 at 4:27 pm

    We are talking very serious taxpayer dollars here…one year alone there was $520,000.00 spent on testing fox scats at the Institute of Applied Ecology, Canberra.
    What does testing actually prove, other than an attempt to convince the punters foxes are here?
    Once we were told it identifies areas foxes are occupying and 1080 baiting can then be applied.
    Now they are just 1080 baiting in “prime fox habitat” anyway.

    All this faulty DNA testing…does it mean Tasmania may get a refund?

  15. J A Stevenson

    August 17, 2011 at 2:12 pm

    Does that work out at $1000000 per scat?.
    A saying from my childhood, “Where there’s muck there’s money” still applies.
    Expect a announcement shortly from the Fox Farce. “Mission successfully accomplished”.

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