DNA splits and lumps

To: "birding-aus" <>
Subject: DNA splits and lumps
From: "Wim Vader" <>
Date: Fri, 23 Feb 2007 09:56:50 +0100

 I have downloaded and read the paper involved (which to me seems a 
prerequisite for having strong opinions on the matter), and nowhere do the 
authors 'make splits and lumps'! What they do, is to draw attention to the fact 
that in most cases the very small fraction of  mitochondrial DNA that they 
examine in the bar-coding project shows clearcut interspecific differences and 
small intraspecific differences. There are a number of exceptions to this 
general rule, though, and as happens so often, these have drawn almost all the 
attention away from the main message, which is: bar-coding can be of great help 
in rapidly identifying bird species from biological material.
These exceptions are of two types: in a number of species there ARE clear 
INTRAspecific differences, and one gets two clusters instead of one cluster. 
The authors remark that these cases may well involve cryptic species, and 
indeed in many of them morphological and biological studies already had 
intimated that these species were not homogeneous. together, these data may 
well utlimately lead to further splitting in these cases.

In the other type of exception the ARE NO clearcut INTERspecific differences in 
this particular part of the DNA. (NB, It is of course quite wrong then to jump 
to the conclusions , as several mailers have done, that ' the DNA is equal': 
there may be lots of differences in other parts!) Also here the authors of the 
present article are commendably careful; they discuss several possible reasons 
for the great similarity of the DNA fragmnants involved, and urge further 

It will therefore definitely be some time, at best, before we can start adding 
and subtracting species from our life lists!

I am a classical taxonomist of crustaceans, not evenbirds, so my words do not 
carry particularly much weight

                                                Wim Vader, Tromsø Museum
                                                9037 Tromsø, Norway

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