[Taxacom] Microspecies (was: GMOs and taxonomy)
Richard Jensen
rjensen at saintmarys.edu
Tue Nov 10 11:57:06 CST 2009
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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