This is a bit of a surprise
result that is not so surprising with the benefit of hindsight. It has always been amazing that it is
possible to double the chromosome count by the two combined genome simply by not
splitting to form replicas of the originals.
This has allowed a wide range of beneficial crops that naturally produce
larger seeds in particular.
Without is we would never have
had bread and plenty of other valuable crops. Now we can induce this behavior,
so it is now a natural first step in hugely improving a given wild stock for
human use. I think that polyploidy is
now coming into its own as we investigate alternative crops as a matter of
course.
I grew up in a world that
generally did not readily experiment with new foods at all. Today that world is turned on its head simply
because a case of anything can be shipped cheaply enough to develop any market. We have all learned to try anything and few
hold back anymore.
In out own environment, the elderberry
should be particularly amenable as a crop and the cattail should be worked with
to produce larger seeds. Both are
presently troublesome but both would be much less so if the fruits are simply
enlarged. I like both because they work
best with wet feet on land otherwise unusable.
In the event we have learned that
our simple model is a little too simple and that there may be a lot more
variation to work with here that may even allow management.
UF research on newly formed plants could lead to improved crop
fertility
by Staff Writers
Researchers analyzed about 70 Tragopogon miscellus plants, a species in
the daisy family that originated in the northwestern U.S. Europe
mated to produce a hybrid offspring, and hybridization was followed by
polyploidy.
A new University
of Florida
Published online in the Proceedings of the National Academy
Because many agricultural crops are young polyploids, the data may be
used to develop plants with higher fertility and yields. Polyploid crops
include wheat, corn, coffee, apples, broccoli and some rice species.
"It could be occurring in other polyploids, but this sort of
methodology just hasn't been applied to many plant species," said study
co-author Pam Soltis, distinguished professor and curator of molecular
systematics and evolutionary genetics at the Florida Museum of Natural History
on the UF campus.
"So it may be that lots of polyploids - including our crops -
may not be perfect additive combinations of the two parents, but instead have
more chromosomes from one parent or the other."
Researchers analyzed about 70 Tragopogon miscellus plants, a species in
the daisy family that originated in the northwestern U.S. Europe
mated to produce a hybrid offspring, and hybridization was followed by
polyploidy.
Using a technique called "chromosome painting" to observe the
plants' DNA, UF postdoctoral researcher and lead author Michael Chester
discovered that while whole genome doubling initially results in a new species
containing 12 chromosomes from each parent, numbers subsequently vary among
many plants.
The paints are made by attaching different dyes to DNA of the two
parent species. Once the dye is applied, there is a match between the DNA of
the paint and of the chromosome.
Under a microscope, the chromosomes appear in one color or the other
(red vs. green) depending on the parent from which they originated. Sometimes
chromosomes are a patchwork of both colors because DNA from the two parents has
been swapped as a result of chromosomal rearrangements.
"One of the things that makes this so amazing is that where we
expected to see 12 chromosomes from each parent (the polyploid has 24
chromosomes), it turns out there aren't 12 and 12, there are 11 from one
parent and 13 from the other, or 10 and 14," Soltis said.
\
"We're hoping through some ongoing studies to be able to link
these results with the occurrence of another interesting phenomenon - the loss
of genes - and also see what effect these changes have on the way the plants
grow and perform."
The polyploid's two parent species, Tragopogon dubius and Tragopogon
pratensis, were introduced to the U.S.
"People have looked at these chromosomes before, but until you
could apply these beautiful painting techniques, you couldn't tell which parent
they each came from," Soltis said.
Of the six populations examined from Washington
and Idaho
"In order for most plants to be able to interbreed successfully,
their chromosomes need to match up," Chester
The two-year study was funded by the National Science Foundation. Other
co-authors include Doug Soltis, a distinguished professor in UF's biology
department, UF undergraduate biology student Joseph Gallagher and Ana Veruska
Cruz da Silva of Embrapa Tabuleiros Costeiros in Brazil and the Florida Museum.
"Among all of the processes that generate biological diversity
in the plant kingdom, genome doubling, or polyploidy, is among the most
prevalent and important," said Jonathan Wendel, professor and chairman
of the department of ecology, evolution, and organismal biology at Iowa State
University, in an email.
"This is an area that is receiving international focus and research attention,
but the system Pam and Doug Soltis are working on is unique."
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