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RE: Species of hosta

  • Subject: RE: Species of hosta
  • From: "Andrew Lietzow" <alietzow@myfamily.com>
  • Date: Tue, 14 Sep 2004 15:01:19 -0500

RE:>> Only new data can refute my conclusions.  

Ben is, of course, 100% correct with this statement.  With the advent of Flow Cytometry, and his application of this analytical procedure as a Taxonomic Criteria, we are now able to look at the Hosta from the inside out.   This is truly a major milestone.   This does not in anyway detract from the work over many decades, even centuries, in extablishing taxonomic criteria for differentiation of taxons into species through examination of *morphological* characteristics.   To the contrary, Ben's work adds to it.  A database field for DNA content, measured in picograms of DNA per specimen, must be added as a field fo the registration database if the database is to become complete.  If such has not already been done, one day it will be with a stroke of the AHS board's pen.  In the meantime, each registered plant has a unique DNA content weight and as this data becomes available, the registration record should be amended to show same.  Right now, the only person in the WORLD that is doing this, of whom I am aware, is Ben Z.   Therefore, he is the "official" registrant of plants, based on this taxonomic criterion.  Unfortunately, my forays into the field is as a DNA "dabbler", with only a little more knowledge than a pollen dabber.     

The next step in taxonomic analysis is DNA sequencing, through RAPD, AFLP, RFLP, or similar. and even that will not resolve all of the controversy.   

The field of genetic analysis, particularly through DNA sequencing, appears to be wide open, primarily because it is expensive to conduct the research but secondarily because it continues to be non-trivial.  In four years of studying and searching, I have only found a couple of published works with Hosta as the primary specimen of interest.  There may be more, but I doubt many.  

The most important actually remains unpublished.  It the work, the researchers introduce to taxonomic analysis a criterion for differentiation of "species" of a specific DNA sequence, to be identifiable with specific primer markers, through RAPD-PCR (Random Amplified Polymorphic DNA - Polymerase Chain Reaction amplification and electrophoresis analysis).    

I believe the researchers were focusing on nuclear DNA, but need to examine this further.  If I, or anyone, can find a "kit" that will allow me to isolate plasmid DNA from nuclear, I think I could make a lot more progress on this question of how many "true species" exist in the genus 'Hosta' and yet, who am I to say?  Stating how many species there are is like the work of an artist, not a mathematician.   Taxonomic analysis is to plants like medical analysis is to humans--no matter how you slice it, in the end, it's still an art and we cannot be 100% certain of much of anything--there are just too many variables.  

I believe in the end, even with the very exacting and exciting analysis that DNA sequencing brings to the table, stating that one particular plant population can be identified as a "species" will still be more qualitative than quantitative.   After all, all plants "evolved" from just a few, right?   Or only a few were created and THEN they evolved... 

Ultimately, we might be able to prove that all species plants are  homozygous for dominant genes and the error factor from having heterozygous specimens polluting the genetically "identical" population pool (i.e. the supposed genetically pure "species" populations in the wild), could be largely eliminated, though doubtfully 100%.  

The examplary work of the astute morphological taxonomists (for the genus Hosta), in the current age the most notable of whom is W. George Schmid,  when coupled with the exacting work of the new-era, macro-molecular genetic analysts, the preeminent investigator being Ben Zonneveld, will be coupled with the DNA fingerprinting/mapping work of some young micro-molecular genetic analyst(s), and we should have a better idea of the number of "true species".   

In the meantime, "Can't we all just try to get along?"    Why do we care so much whether its 23 or 41?  What we really NEED to be doing is to identify the DOMINANT genes and the RECESSIVE genes among cultivars, and so-called species.    Who will name these genes and who will associate them with specific specimens that carry them as Dominant genes?   Has the book already been written and I've just missed it?   Are we at the stage where we can't really move forward because we're stuck until we "know" whether it's 23 or 41.   Can we move this along toward something potentially much more important?  

Who wants to help build a database of named genes?   Who wants to be on that committee?  

My 2 cents worth... 
Andrew in Des Moines

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