permaculture

[Lawrence London <lfljvenaura@gmail.com>]

Scientists Propose Creation Of New Type Of Seed Bank (10/20/2008)
http://www.wildbiology.com/research/Scientists_Propose_Creation_Of_New_Type_Of_Seed_Bank.asp

Scientists Propose Creation Of New Type Of Seed Bank (10/20/2008)

 *While an international seed bank in a Norwegian island has been gathering
news about its agricultural collection, a group of U.S. scientists has just
published an article outlining a different kind of seed bank, one that
proposes the gathering of wild species -- at intervals in the future --
effectively capturing evolution in action.*

In the October issue of Bioscience, Steven J. Franks of Fordham University,
Susan J. Mazer of the University of California, Santa Barbara, and a group
of colleagues, have proposed a method of collecting and storing seeds of
natural plant populations. They argue for the collection of many species in
a way that evolutionary responses to future changes in climate can be
detected. They call it the "Resurrection Initiative."

"In contrast to existing seed banks, which exist primarily for
conservation, this collection would be for research that would allow a
greater understanding of evolution," said Franks.

"This seed collection would form an important resource that can be used for
many types of research, just as GenBank -- the collection of genetic
sequences and information -- forms a key resource for research in genetics
and genomics," said Franks.

"Typically, seed banks are focused on the preservation of agricultural
species or other plant species of strong economic interest, say, forest
species, forest trees," said Mazer. This is to make sure that scientists
can maintain a genetically diverse seed pool in the event of some kind of
ecological calamity that requires the replenishing of seeds from a certain
part of the world or from certain species. "But that implies a relatively
static view of a seed bank, a snapshot forever of what a species provides."

Evolutionary biologists recognize that the gene pool of any species is a
dynamic resource that changes over time as a result of random events such
as highly destructive climatic events like hurricanes, but also through
sustained and ongoing processes like evolution by natural selection.

While most scientists agree that the climate is changing, the extent to
which species will be able to evolve to keep up with these changes is
unknown.

According to the article, the only way that scientists can detect the
results of those sorts of calamitous changes -- and test evolutionary
predictions about what sorts of changes might occur over time -- is to
sample seed banks in a repeated fashion. Then they must compare the
attributes of the gene pools that are sampled at different times to a
baseline.

"One way that we can obtain this baseline is by collecting seeds at a given
point in time and archiving them under ideal environmental conditions, so
that they all stay alive, and so that 10, 20, and 30 years down the road,
we can compare them to seeds that we collect in the future to see how the
gene pool has changed," explained Mazer.

This approach will allow a number of things that a one-time, seed-sampling
event doesn't. Scientists can evaluate the result of the effects of climate
change, land use change, and other kinds of environmental changes such as
the spread of disease on the gene pool.

"Currently seed banks don't allow this for a couple of reasons," said
Mazer. "First, they focus on species that have been under cultivation for a
long period. Species that have been under cultivation have relatively low
levels of genetic variation -- because we have been selecting them only for
the attributes that we want. Wild species, by contrast, contain a high
degree of genetic variation in almost any trait that we might examine."

Agricultural species are often selected to have a predictable flowering
time, a predictable seed size -- and a predictable degree of tolerance for
drought, salt, or heavy metals. By contrast, wild species retain a much
greater degree of genetic diversity in all of these traits.

Mazer explained that scientists don't know whether or not the environmental
changes that are ongoing, due to changes in climate or land use practices,
are reducing the amount of genetic variation in the wild. If they are, the
only way it can be detected will be by sampling representative seeds from a
large number of populations at very regular intervals.

"The approach that we would use is not simply to collect seeds over various
time intervals and to archive them, but in the future to raise them in a
common environment comparing seeds that were collected in 2010, 2030, and
2050, for example," said Mazer. "If we found, for example, that the plants
that come from seeds that were collected 50 years from now flower much
earlier than those that were collected today, we could logically infer that
natural selection over 50 years had favored plants, that is genotypes that
flowered earlier and earlier, relative to those that delayed flowering."

Mazer explained that scientists and the public have been thrilled recently
by an increase in the understanding of the value of seed banks, and in
particular with the seed bank that is underway in Norway, called the
Svalbard Global Seed Vault, on the island of Spitsbergen.

"However, that kind of seed bank doesn't finish the job," said Mazer. "The
Norwegian seed bank is planning to preserve hundreds of thousands of
varieties of agricultural plant species, but most of those samples
represent only a tiny fraction of that which you would find in a wild
population of a wild species." Nor does it allow for insights into the
evolutionary process, enabled by the combination of seed banking and
subsequent raising of plants as proposed by the "Resurrection Initiative."

*Note: This story has been adapted from a news release issued by UC Santa
Barbara*