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

Re: hosta-open DIGEST V1 #483


I appreciate your joining us.  We need some geneticists among us (I am
including you Ben).  I think, however, that we could all use a simple
explanation of transposable elements with an example such as seed color in
corn.  I fear we are beginning to float way over everyone's head.  I have
often wondered if Hosta variegation could at least be partially explained by
transposable elements.  I have figured that in our lab we see a new
variegation in something less than 10,000 individuals, which is clearly not
a simple mutation process.  I think we need to get terminology straight
before any arguments proceed.  Is the movement of an element a mutation or
is there a better way to describe this?  What is a position effect?

Ben thinks that H. Patriot -- Minuteman and probably other wide margined
thick leaf 'sports' are tetraploids not some other type of change.  I admit,
that I would be more comfortable with a chromosome count, but Ben's
techniques should show ploidy.

I would like to see a simple explanation of how you think the transposable
elements are involved in streaking.  And, especially in Hosta such as
Revolution, Allegan Fog, and our Fuzzy (all fortunei from what I can see)?
How about the net type variegations of Strip Tease, Spilt Milk, and Winter
Lightning?  I would also invite Ben to give his explanation (or at least
some speculation) for these phenomena, as clearly we have a difference in
opinion here.

Jim Anderson

-----Original Message-----
From: halinar@open.org <halinar@open.org>
To: hosta-open@mallorn.com <hosta-open@mallorn.com>
Date: Tuesday, August 10, 1999 2:24 AM
Subject: Re: hosta-open DIGEST V1 #483

>>Jim Anderson had asked a question (number 1) regarding
>>similarities/differences between variegation in daylilies and
>>hostas. I had declined to participate in this question because of my
>>limited familiarity in daylilies.
>There are very few variegated daylilies and they are mostly unstable.
>A variegated seedling will show up from time to time, but they tend to
>be mericlinal chimeras and few form a stable periclinal chimera.
>>I summarized the concepts defined by Jones(1934) wherein chimeras
>>(multicolored adjacent tissues) are a result of mutations within
>>specific cells which create two or more colors within cells and
>>subsequent, corresponding tissues.
>I think hosta people need to get away from thinking in terms of
>mutations as the cause of variegation in hostas and start looking at
>the problem from a logical point of view.  First, I don't know of any
>other plant genera like hosta.  Hostas are NOT mutating at any higher
>rate then any other plants.  When you look at any other plant genera
>you don't see the level of variegation that you see in hosta.  If
>hosta variegation was due to mutations then you would see the same
>level of mutations in other plants.  I know the Great Ben proposes
>mutations as one cause of hosta variegation and sporting, but Ben
>doesn't know much about botany.
>Secondly, if you propagate enough hostas you see that certain types
>keep reappearing.
>Variegation in hostas is most likely due to either transposable
>elements or some other mechanism that turns genes on and off.
>Some time ago I gave Ben a clue to figuring this out, but apparently
>he doesn't know enough about higher plants and apparently doesn't have
>the observational skills to figure this out, besides not knowing how
>to propagate hostas.  If you look at Francee in the spring you see
>that the margins are lighly yellow when the new leaf is still small.
>If you look at Patriot you see that the edges of new leaves are
>yellow, but a deeper yellow.  The leaves of Patriot have a wider edge,
>the color of the center is a darker green and if you feel the leaves
>they have a thicker, heavier feel to them.  If you propagate enough
>Francee you see this Patriot form showing up from time to time, but
>sometimes not as intense as Patriot.  Also, you get light green forms
>from time to time.  This is a POSITION effect.  I'm amazed that the
>Great Ben couldn't figure this out, especially considering he is
>suppose to be knowledgeable about fruit flies where position effects
>were first studied.
>This spring I had five sports out of Whirlwind from 7 plants.  Three
>of the sports had leaves that were folded in half with a narrow white
>center.  After the 4-5th leaf the new leaves started getting flater,
>but still with a thin center.  Now the newest leaves are pretty much
>like Whirlwind.  All three plants that had this initial type of leaf
>did this gradual change.  This behavior is not due to mutations.
>In cats calaco coloring is due to turning off of one of the X
>chromosomes.  Some cells have the paternal X on while other cells have
>the maternal X on.  When the X chromosomes get turned on/off
>determines the calaco pattern you see.  Streaked hostas are the calaco
>cats of the hosta genus, except it's not a X/y based sex chromosome.
>In a two layer histogenic structure the corpus (L2) doesn't have the
>organized apical initials like the L1 layer does.  Therefor, the cells
>in the L2 apex can be a mosaic pattern of genes that are turned on or
>off, or a position effect through a transposable element - this would
>result in a streaked hosta.  A streaked hosta would revert to a
>"stable" edged/center variegation pattern when the cells in the apex
>of the L2 layer all revert to having the transposable element at the
>same location.  A edged/center hosta can revert to a streaked form
>when some of the transposable elements shift position resulting in a
>mosaic pattern in the L2 apex.
>Getting a good understanding of transposable elements is difficult.
>Genetics textbooks in the 60's and 70's don't discuss them because
>they were not understood well at the time, and by the 80's and 90's
>genetics textbools were being written from a biochemical and molecular
>biology point of view and also mostly ignore transposable elements.
>For those who might want to do some searching of the literature,
>search for articles by Barbara McClintock.
>Now, I wonder how long it will be before I see this showing up in the
>Hosta Journal as Ben's latest theory on variegation in hostas.  I
>certainly hope he will give me some credit!
>Joe Halinar
>To sign-off this list, send email to majordomo@mallorn.com with the

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