How to Catch Evolution in the Act

Scientists collect seeds to study how plants adapt to climate change.

October 21, 2008, 4:28 PM

Oct. 22, 2008— -- Scientists are planning to take advantage of global climate change and catch evolution in the act. They hope to collect millions of seeds from wild plants over specific time intervals and, for the first time, document how individual plants adapt to changes in the climate.

"Changes in climate are already beginning to have detrimental effects on many species, and we want to understand that," said evolutionary biologist Steven Franks of Fordham University, one of the leaders of the project.

The project is called the "Resurrection Initiative" because the goal is to provide future scientists with pristine seeds collected during this period of relatively rapid climate change. Someday, those seeds could be planted alongside members of the same family so that changes could be documented, thus providing a better understanding of the fundamentals of evolutionary change.

This seed bank would be different from the many other existing banks, including the now-famous Svalbard Global Seed Vault on the island of Spitsbergen, Norway, where seeds are being collected from around the world to help preserve species that are now in danger of going extinct. The purpose of the new bank would be basic science on evolutionary changes, with the possible goal of using that information to help stop some species from dying out, not simply replacing them after they are gone.

"It's a perfect opportunity right now to understand how organisms evolved in response to changing conditions," said Franks, indicating that there is some urgency in getting the project going on a broad scale as soon as possible. Leading experts on various aspects of evolution, from an array of institutions across the country, are involved in the project.

The evolutionary seed bank is the brainchild of Arthur E. Weis, who is now at the University of Toronto. Weis invited the experts to a meeting last year at the University of California, Irvine, when he was on the faculty there. The meeting, sponsored by the National Science Foundation, resulted in a paper published in the October issue of the journal BioScience, outlining the project. Funding has not yet been secured, but the NSF, which sponsors most academic research in this country, is clearly interested.

Evolutionary biologist Susan Mazer of the University of California, Santa Barbara, an expert on wild flowering plants and a member of the group, said one goal is to create baseline data "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."

The genesis of the project actually dates back a few years ago when Franks, lead author of the paper, was Weis's graduate student.

"We were both interested in looking at evolutionary responses to climate change," Franks recalled. Franks zeroed in on plant that thrives in southern California, Brassica rapa, or wild mustard. He began collecting seeds from several areas, documenting where and when he collected then, and when the individual plants flowered -- some early in the season, some much later.

California went into a five-year drought, laying a perfect framework for studying whether that sudden climate change forced evolutionary changes in the plants. At the end of that time, Franks collected seeds from the same plants, and then planted both the archived and the newly collected seeds in a controlled environment.

"There was an evolutionary shift to earlier flowering time following the drought," Franks said in an interview. Using the wide range of tools now available to geneticists, he was able to determine that the shift was reflected in the genes of the plants, or as biologists would say, the later plants selected (mutations) for earlier flowering.

It wasn't a huge change, ranging from 1.9 days in one group of plants to 8.6 days in another. The scientists call it a "microevolutionary change," but it was significant. Earlier blooming allows the plants to take advantage of a cooler spring, and thus produce stronger seeds that are more likely to survive in a drier climate. It was clearly a case of capturing evolution in the act.

That is precisely the way evolution works. Not giant leaps, but tiny steps.

However, what works for one plant may not necessarily work for another. So the scientists want seeds from many plants to capture the many phases and directions of evolution.

"By rearing samples of ancestral populations, we could resurrect actual genotypes that existed centuries ago," they state in their paper. "Differences between modern and ancestral populations would directly document evolutionary change over known time intervals. We call for an organized effort to accomplish what earlier naturalists did not: systematic collection and preservation of current genetic diversity for future analyses of evolution of phenotypes in conjunction with environmental change."

It could be possible to begin the project on a limited scale, with very little funding, but the scientists believe that would waste precious time. They want to start out on a large scale, involving many institutions and many different types of plants.

"The resurrection approach may be especially pertinent given current global climate change, which is occurring at rates and scales not seen for millennia," they state in their paper.

In other words, the time to strike is now.

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