[Taxacom] Microspecies (was: GMOs and taxonomy)

[Haveman, Rense]

Hi Dick,

If we want to reflect the evolution of a group in our taxonomy, in
taxonomy practice it has proved to be very hard to recognise apomict
entities as subspecies. Why? If we want to group those subspecies under
one species that are more related - have one ancestor - that the ones
grouped under another species, we have to know which entities have the
same parent-species. This is exactely the point why this is impossible.
One of the reasons not to recognise apomicts as subspecies is their
uncertain (direct) ancestry and (inter-)relationships. Due to (mostly?)
reticulate evolution you will end up summing all apomict entities under
one superspecies. In the end this won't help getting a clear overview
over which entities are worthwile recognising or not, I guess. That is
why most (European?) taxonomists working on (plant) apomicts consider
all apomict entities as species, or at least admit that this reflects
the genetical structure of the genus best.

Kind regards,

R. (Rense) Haveman 
Inventarisatie en Monitoring Natuurwaarden Defensieterreinen

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-----Original Message-----
From: taxacom-bounces at mailman.nhm.ku.edu
[mailto:taxacom-bounces at mailman.nhm.ku.edu] On Behalf Of Richard Jensen
Sent: dinsdag 10 november 2009 18:57
To: Kenneth Kinman
Cc: taxacom at mailman.nhm.ku.edu
Subject: Re: [Taxacom] Microspecies (was: GMOs and taxonomy)

Hi Ken,

I see no good reason why apomicts could not be recognized as subspecies 
(or varieties), except for the fact that they are apomicts. But then we 
must ask if they are facultative or obligate apomicts and whether or not

they produce viable pollen, as some apomicts do. All of this makes the 
question of their status more difficult to address.

If we know that a particular apomictic line is obligately apomictic, and

produces inviable pollen, then I see no reason to not treat it as a 
species. On the other hand, if the apomictic line produces viable 
pollen, and can then cross with either other non-apomictics of its 
parent species (or other species), then I would argue for subspecies or 
varietal status rather than species status.

Cheers,

Dick J

Richard Jensen, Professor
Department of Biology
Saint Mary's College
Notre Dame, IN 46556
Tel: 574-284-4674



Kenneth Kinman wrote:
> Hi again,
>        Well, subspecies of sexual organisms are also recognized on the
> basis of morphological (often minor) differences.  However, this does
> not prevent them from interbreeding at the edges.
>        Likewise, even clonal apomictic populations aren't immune from
> such genetic exchange when apomixis breaks down.  For example, I
suspect
> that some researchers recognize too many dandelion species simply
> because they don't have the data that would demonstrate that apomixis
> breaks down where such populations meet and overlap.  Perhaps some of
> the splitters should refrain from describing microspecies as full
> species unless that have some data indicating a probable lack of
> apomictic breakdown.  They could always give them subspecies names
until
> more such data is available.  There seems to be a huge discrepancy
> between splitters and lumpers on the numbers of dandelion species.  I
> tend to believe that splitters should show more restraint and name
> subspecies rather than species when in doubt.
> ====================================
> Richard Jensen wrote:
> Hi Ken, 
> Apomictic microspecies are usually recognized on the basis of some
> (often minor) consistently recognizable morphological difference. That
> is, a given microspecies is a population of morphologically uniform
> individuals that differ from other such populations. Given that
> microspecies are clones, they are by definition reproductively
isolated
> from other such entities and can be viewed as species by any of
various
> species concepts, e.g., biological, genetic, morphological, phenetic,
> phylogenetic. 
> As you note, some consider them separate species and others consider
> them variants (formae apomictae) of a single species (splitters vs.
> lumpers, respectively). The status they are accorded will depend on
the
> perspective of the taxonomist dealing with them.
>
>
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