Re: No New Messages, Sports and Transposable Elements
- Subject: Re: No New Messages, Sports and Transposable Elements
- From: andrewl <firstname.lastname@example.org>
- Date: Sun, 22 Apr 2001 21:27:26 -0500
RE:>> Perhaps you may have forgotten...
I obviously did not recall that you posted this one specifically.
Even so, I don't know that it hurts to have it referenced again as new
members may have joined since your last posting. From the article
that you and I are both citing (because it DOES offer an excellent review
of the literature), I find this statement:
"The vast majority of variegated-leaf chimeras have arisen by spontaneous
nuclear or plastid mutation".
From some of the literature that I am reading, written from a molecular
geneticists point of view, some researchers seem to believe that many (Hosta?)
sports (variegations due to chimeras or mutations) could be due to transposable
elements. I intend to do some work on this in the near future,
preferably utilizing a PCR test. Unfortunately, I need to understand
microsatellites, linkage mapping, and the whole DNA sequencing process
better; I'm a ways off from that. Don't even know how to prepare
the samples for the PCR test but that is a technical hurdle that can be
overcome (we do have a blender, so maybe I can up a batch right here
in the kitchen sink! <g>) We are fortunate here in Iowa to have a few
folks that do know how to do this. If we can find a single Starlink
gene in about four bushels of corn, there ought to be a way to isolate
the genes for, e.g. the sport of H. Blue Angel, H. White Angel.
However, I am still trying to figure out how to intelligently phrase
some of the questions that remain to be asked! I think there
are adequate means to examine many of the hypotheses. (see http://www.dna.iastate.edu/mainpage.html)
It would be good to isolate some mappable genes with linkage to coloration.
If there are multiple duplications of gene sequences, and these correlate
to genes known to be transposable in other eukaryotic plants, could clearer
explanations be far behind? Eventually, I may need to know how to
work that BLASTP or FASTA software, which could lead to a need to do some
clustering of Linux servers, and on ad infinitum...
As for Ben's mitotic recombination, I'm more than a little curious about
this process. I see that there has been a lot more research with
E. Coli and yeast, yet when the authors (Pogany and Lineberger) refer to
"spontaneous mutation, induced mutation, sorting-out from variegated seedlings",
are some of these events possibly mitotic recombination? We
talk about this phenomena a lot, but just what in the bejebbers IS "mitotic
recombination"? I found an animated overview of the process
here-- http://www.people.virginia.edu/~rjh9u/lohanim.html which
helps a little. Is this a recombination of alleles that results from
the process of mitosis only? Sounds right, but if you say, "no duh"
I'm going to feel pretty stupid. Heterozygosity becomes homozygosity,
or homozygosity becomes heterozygosity?
While mitotic recombination may occur but as a rare event, transposable
elements may lead to variegation in plants with much greater frequency.
If it is likely that some mitotic recombination is occurring in other plants,
at what frequency might this be occuring in Hosta? Certainly chimeric
changes are common that are NOT any kind of more permanent rearrangement
of the DNA molecules yet some chimeras may appear to be simple chimeric
changes when they are in fact a result of mutations or mitotic recombinations.
(See http://www.agron.missouri.edu/mnl/72/47peterson.html , specifically
the last paragraph which refers to a 2 out of 400 frequency in Maize).
Keep in mind that I certainly don't KNOW what I'm talking about.
That should/could change over time, and I sure hope so as I continue to
have interest in this area. In the interim, I'm glad to see that
the discussions continue as we dig for answers. I expect to
have some meetings soon with people who understand much more about these
things from a molecular point of view but if you or anyone else feels they
have a handle on this, please jump in and help explain some of these phenomena
so we can gain ground more quickly.
Jim, I know you like to keep things stirred up so that we can learn
more about our beloved genus, to learn more about what makes them tick,
and it would be good to find some more geneticists that were willing to
respond. Hopefully we can find someone who might assist, since Ben
is snubbing us. <g>
I don't know about you, but I am a much kinder/gentler person
after I've had a chance to spend some time in the Hosta patch so it's sure
nice to see those crowns breaking dormancy...
Hugs and Kisses!
#1 Plantsman at http://hostahaven.com
1250 41st St
Des Moines, IA 50311-2516