hort.net Seasonal photo, (c) 2006 Christopher P. Lindsey, All Rights Reserved: do not copy
articles | gallery of plants | blog | tech blog | plant profiles | patents | mailing lists | top stories | links | shorturl service | tom clothier's archive0
Gallery of Plants
Tech Blog
Plant Profiles
Mailing Lists
    Search ALL lists
    Search help
    Subscription info
Top Stories
sHORTurl service
Tom Clothier's Archive
 Top Stories
Disease could hit Britain's trees hard

Ten of the best snowdrop cultivars

Plant protein database helps identify plant gene functions

Dendroclimatologists record history through trees

Potato beetle could be thwarted through gene manipulation

Hawaii expands coffee farm quarantine

Study explains flower petal loss

Unauthorized use of a plant doesn't invalidate it's patent

RSS story archive

Discussion on Origin of Sports

Hosta Scholars All,

As promised I will begin our informal discussion on the subject at hand.
Joe Halinar has asked me to copy to him current messages thru hosta-open
because he is on digest service and there may normally be  a delay in
communication for him..

We are reviewing the technical aspects of three articles on the orign of
sports authored by Ben Zonneveld. Each is different in some respects but
have a common message, i.e. that there are three causes of sports. I
will list these causes in the order that they are listed by Ben.
   Mitotic Recombinations
   Chimeral Rearrangements
   Nuclear Mutations.

When Ben's  last article was written, I prepared a critiqe on May 24,
1999. I sent it to hosta-open for comments. It raised little concern.
The issues are still unresolved...that there is incorrect information
being published in the AHJ. I will repeat the critique in a simplified
form so that readers will get a feel for the technical nature of the
points that I was trying to make. They still remain and warrant
discussion, for educational purposes if for no other reason. A  shorter
redacted version of my critique follows:


 I am urged to comment on a recent article written in the Hosta Journal
 Vol.30.1 by Associate Professor Ben Zonneveld in which he tries to
 develop a rationale for his theory for the causes for sports. While the

 causes for sports might normally interest only other Geneticists,  I
find the
 article so faulty that a response seems appropriate to correct some

 He raises questions...Are they really identical or only similar? Should

 they have different names if they are only similar? If they are
 identical, could they have a single name? He hopes to answer these
 questions by focusing on justification of names by discussing his
 theory  that there are three causes for hosta sports, i.e. (1) mitotic
 recombination, (2) chimeral rearrangement and (3) mutations. He states
 that "for our purposes we will treat mitotic recombination and
 mutations as processes that mainly take place in the DNA of nucleus and

 not in the DNA present in the other organelles of the cell" , (the
 plastids, for example).

 The faults I find in the article is that it is self-serving, it is
 biased, it is incomplete and it is in error in many repects. There is
 literary review to discuss the work and the views of other workers in
 field. It does not discuss the histological basis for chimeras, the
 "tunica-corpus" organization of cell layers in the meristem( after
 Schmidt 1924), nor the identification of the two-three layer apices
 common in monocots according to Stewart and Dermen (1979). He ignores
 need for discussing "apical initials" within each apical layer of the
 meristem. He does not discuss the fact that when cells from an inner
 layer (L2 , for example) which take over the position of  cells from
 outer layer, "displacement" occurs, while "replacement"  occurs when a
 periclinal division of a cell occurs allowing for layer switching (per
Stewart and Dermen 1970).

 He does not mention the work of Dr. Michael Marcotrigiano, world
 authority on chimeras and  Associate Professor of the Dept. of Plant
 Science, Univ. of Mass., Amherst, who explains how plastid mutations
 leads to variegation because of the growth and distribution of
 heteroplastidic cells. Marcotrigiano  states that "the most common
 of chimeral variegation is spontaneous  mutation in the pathway of
 chlorophyll synthesis or plastid morphology. These mutations are
 generally chloroplast mutations rather than nuclear mutations".
 Marcotrigiano then explains the genetic rationale for these
 Ben does not discuss the distribution and sorting out of mutated
 plastids  in cells, as described by many workers. Nor does he discuss
plastid mutations that often
 take place during various stages of embryogenesis according to

 Thus, the background of cytoplasmic and nuclear genetic factors are not

 covered to explain their role in chimeras. His theory is contrary to
 views of  classical research workers in this field (Schmidt,
 Stewart and Dermen, Tilney-Bassett, Vaughn and Marcotrigiano).

 The author states "that for our purposes, we will not consider DNA
 changes in the organelles of cells(the plastids). This statement seems
 suspect and inappropriate in a scientific discussion. Is it not the
 purpose of a scientific inquiry  to look at all causes of phenomena
 under study? If the purpose is to consider only the author's views and
 theories, is not the discussion slanted, biased and incomplete at the
 outset?. Why has not Ben reviewed the scientific literature? Why has he

 not mentioned Vaughn's work on plastid mutations and cytoplasmic
 inheritance? We will do so as our discussion proceeds in future days.

 If the purpose of Ben's article was to inform  readers of the
 scientific facts by use of his theory, I must say I find his arguments
 incomplete, in error on several occasions, biased and non-convincing.
 Jim Hawes
To sign-off this list, send email to majordomo@mallorn.com with the

Back to our discussion...............
If readers wish to get even more backgound on scientifc achievements
regarding chimeras in Hostas, I suggest you go to the Webpage of First
Look of Region One which has become famous in recent days. Carol
Brashear and her seven dwarf helpers have posted the article written by
Dr. Kevin Vaughn "Chloroplast Mutants in Hostas from  the AHS Bulletin
11 This is a classical work of research in Hosta . Please don't miss
reading it. I want to personally thank Carol for this help in getting
information for all to read. I will attempt an interpretation and
summary of this very important work the next time I enter the
discussion....perhaps tomorrow.  Meanwhile you are invited to put in
your two cents worth of observations, opinions and facts. . Feel
free...we are open  for discussion.

Jim Hawes

To sign-off this list, send email to majordomo@mallorn.com with the

 © 1995-2015 Mallorn Computing, Inc.All Rights Reserved.
Our Privacy Statement
Other Mailing lists | Author Index | Date Index | Subject Index | Thread Index