Thanks for all that, Colin. I don't understand how DNA analysis gives a
population estimate. Is it to do with the number of ancestors each bird must
have had in order to have that amount of variation in its DNA?
And if you could get the necessary samples, would you know when that population
estimate was valid for? I assume the estimate derived from, say, 20 samples
collected 100 years ago would be no different to 20 collected today, yet the
population is likely different today to 100 years ago. Even 100 years ago there
might have been a tiny fraction of the population 200 years ago.
Peter Shute
> -----Original Message-----
> From:
> On Behalf Of
> colin trainor
> Sent: Monday, 12 August 2013 10:06 AM
> To: Ross Macfarlane (TPG);
> Subject: [Birding-Aus] DNA confirms elusive Night Parrot found
> Determining NParrot populations from bits of existing
> specimens would be problematic (recognising their incredible
> value and fact you don't want major
> damage) ie. availability of tiny bits of dried
> [non-preserved, and therefore with DNA increasingly degraded]
> flesh from "footpads" or from within a feather - most likely
> from specimens
> >100 years old.
>
> Samples size - if you could get some fresh or well preserved
> NParrot tissue or blood, you might get an estimate of
> population number, but probably with very broad confidence
> limits (e.g. with one bird - Result = 10,000 individuals,
> made up 95% confidence limits = population is within the
> range 100 to 20,000 birds), but with additional samples it
> may get closer to reality, and narrower confidence limits.
>
> You might need say 3-5 samples to get an ?ok result, but need
> more to refine it. Sample size would be critical is getting
> an estimate close to "reality".
>
>
>
>
>
> > From:
> > To: ;
> > Subject: Re: [Birding-Aus] DNA confirms elusive Night Parrot found
> > Date: Sun, 11 Aug 2013 11:48:08 +1000
> >
> > Colin, it's actually very feasible, in fact highly
> important DNA has
> > been extracted from early human fossils that are 100s or
> thousands of
> > years old, that has been used to build a picture of human
> evolution.
> > DNA extracted from frozen mammoth carcases in Siberia have
> led to some
> > researchers to propose reviving mammoth as a species (I truly hope
> > this does not happen, but that's not a discussion for
> here.) The same
> > has been proposed for thylacines using DNA extracted from
> preserved joeys in museums.
> >
> > In other words recovery of DNA from museum specimens is
> > well-established science. It doesn't need to be a complete genome,
> > just enough long fragments to distinguish night parrot from its
> > closest relatives (presumably ground parrot and western ground
> > parrot.)
> >
> > Also distinguishing between human and parrot DNA would be a very
> > simple exercise - much more so than for ancient humans as
> described above.
> > Basically the scientists can look at a series of bands on a
> screen and
> > see which ones are human and which non-human, almost as
> easily as they
> > could distinguish a human and a bird footprint.
> >
> > -----Original Message-----
> > From: colin trainor
> > Sent: Saturday, August 10, 2013 7:15 PM
> > To:
> > Subject: [Birding-Aus] DNA confirms elusive Night Parrot found
> >
> > DNA - Most specimens (?all but 3 perhaps) collected before 1900, so
> > not sure how useful it would be.
> >
> > I'm ignorant of molecular approaches, but this detailed type of
> > analysis may not be possible on gnarly old specimens
> (?better on blood
> > and fresh tissue? - of which there is none)
> >
> > >>>>>>>>>>>>
> >
> > To:
> >
> >
> >
> >
> >
> >
> > Subject:
> >
> > DNA confirms elusive Night Parrot found
> >
> >
> >
> >
> > From:
> >
> > Andrew Hobbs <>
> >
> >
> >
> >
> > Date:
> >
> > Sat, 10 Aug 2013 14:22:41 +0800
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > There are apparently 22 known specimens in various museums
> around the
> > world. I would think it quite possible to use DNA analysis
> on those
> > to make some estimates of population sizes etc. and their
> relationship
> > to the recent samples. I would be surprised if that is not already
> > being done or at least considered.
> > Cheers
> >
> > Andrew
> >
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