[Taxacom] Fw: DNA only descriptions

Sat Aug 21 08:35:27 CDT 2010

Kim, Stephen and Ken, and Taxacomers,

I strongly suspect that most morphologically defined species are valid, and
that as Stephen says, problem species, or cryptic species, are not the norm. 
Perhaps cryptic species are as I describe below.  That is, cryptic species 
are an early pre-stage in the process for forming morphological species, and 
that most, if not all, species go through the same process.

It could also be that what we observe as cryptic species were, in the not very 
distant past, one species that is splitting into 2 or more.  In other words, we 
are at the point in history where what was one species is in the process of 
becoming more than one species, perhaps even sympatrically because of 
local conditions, but certainly allopatrically.  

We create the dendrograms to show what we think happened many years ago 
to what we now see as distinct morphological species
.  
We are now observing that the splits occur cellularly before they occur 
morphologically.  I think we can handle that.

But is would be nice if we could count on the DNA boys & girls to willingly help 
us out when the occasions arise.  We build the hierarchy, they figure out what
is happening to the splitting species.  Wouldn't working together be nice?

Robin

----- Original Message ----- From: "Stephen Thorpe" <stephen_thorpe at yahoo.co.nz>
To: "Robin Leech" <releech at telusplanet.net>; "Kim van der Linde" <kim at kimvdlinde.com>
Cc: <taxacom at mailman.nhm.ku.edu>; "Kenneth Kinman" <kennethkinman at webtv.net>
Sent: Friday, August 20, 2010 7:48 PM
Subject: Re: [Taxacom] DNA only descriptions

[to Robin] steady on old man! :)

I think the DNA boys and girls have two thoughts stuck in their minds, which
seem sensible enough on the face of it, but deeper down lack substance ...

(1) it would be good for identification to be automated, and this would probably
have to be done by DNA analysis

(2) if you describe a species without DNA, then you run the risk of your new
taxon actually being a complex of cryptic species

Let me discuss each in turn:

(1) good for whom? Good for some, certainly. How much effort should go in to
trying to make this a reality? Does this mean we should all stop descriptive
taxonomy and work on developing this idea instead until it is a reality? What if
it can't be done after all? Might not this idea just rip the guts out of
taxonomy, leaving an empty and uninteresting shell? What if you enjoy trying to
identify things? What if it really does require a spark of talent that can't be
automated?

(2) IN THEORY this is true, but:
(2a) this is no argument for not also describing the morphology; and
(2b) "cryptic species" seem a bit dodgy to me - maybe you can find as many of
them as you look for? Maybe these genetic lineages are not what we mean by
species, anyway? I bet most good morphospecies are a single species, and that
problem cases are relatively few and far between...

Stephen

________________________________
From: Robin Leech <releech at telusplanet.net>
To: Kim van der Linde <kim at kimvdlinde.com>; Stephen Thorpe
<stephen_thorpe at yahoo.co.nz>
Cc: taxacom at mailman.nhm.ku.edu; Kenneth Kinman <kennethkinman at webtv.net>
Sent: Sat, 21 August, 2010 1:26:35 PM
Subject: Re: [Taxacom] DNA only descriptions

No, Kim, that is NOT what you do. You are using all the base
morphology information to give you a very select set of specimens
to examine for their DNA.

All the data referring to all the rest of the hierarchy (Phylum down
to genus) and relationships has been given to you on a platter.

And even more, all the other species in the genus, which are known
morphologically, have already been separated away from the select
set of specimens on which you are going to perform your DNA testing.
These specimens are, apparently, morphologically indestinguishable.

Now, having run your DNA test, let us say that you find what amounts
to 3 distinct species.

This is where I would like to come in and as a morphological taxonomist,
examine separately the 3 species, to look for morphological features missed
previously.

I feel that this is where the DNA boys have a distinct role to play, and one
that dovetails into the morphology. When I find the morphological features -
and trust me, I will - you and I will then describe 3 species. We will use
all the morphological features to do this, but we will also mention the DNA
as part of the process. The DNA analysis is not the process in and of itself.
It is but a wee step.

Robin

----- Original Message ----- From: "Kim van der Linde" <kim at kimvdlinde.com>
To: "Stephen Thorpe" <stephen_thorpe at yahoo.co.nz>
Cc: <taxacom at mailman.nhm.ku.edu>; "Kenneth Kinman" <kennethkinman at webtv.net>
Sent: Friday, August 20, 2010 5:58 PM
Subject: Re: [Taxacom] DNA only descriptions

> 
> 
> On 8/20/2010 7:35 PM, Stephen Thorpe wrote:
>>> In my opinion, the crucial aspect we should not forget is that we use
>>> morphology
>>> as a proxy for genetic differences
>> 
>> IT DEPENDS WHAT ONE IS DOING! Descriptive taxonomy, or "systematics"?
>> Descriptive taxonomists would still describe morphology even if systematists
>> knew EVERYTHING about the genetics ...
> 
> Sorry, no, you can describe a species using DNA only. It is desirable,
> no, but we could do it. And with cryptic species, that is exactly what
> we do.
> 
> Kim
> -- http://www.kimvdlinde.com
> 
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