The DNA evidence is in, and Ben Franklin didn't do it.
Invasive Chinese tallow trees have overrun thousands of acres of tall grass coastal prairie on the US Gulf Coast. Credit: Rice University
Genetic tests on more than 1,000 Chinese tallow trees from the United States and China show the famed U.S. statesman did not import the tallow trees that are overrunning thousands of acres of U.S. coastal prairie from Florida to East Texas.
"It's widely known that Franklin introduced tallow trees to the U.S. in the late 1700s," said Rice University biologist Evan Siemann, co-author the new study in this month's American Journal of Botany. "Franklin was living in London, and he had tallow seeds shipped to associates in Georgia."
What Franklin couldn't have known at the time was that tallow trees would overachieve in the New World. Today, the trees are classified as an invasive species. Like Asian carp in the Great Lakes and kudzu vines in the eastern U.S., the trees are spreading so fast that they're destroying native habitats and causing economic damage.
Each tallow tree can produce up to a half million seeds per year. That fertility is one reason Franklin and others were interested in them; each seed is covered by a waxy, white tallow that can be processed to make soap, candles and edible oil.Siemann, professor and chair of ecology and evolutionary biology at Rice, has spent more than 10 years compiling evidence on the differences between U.S. and Chinese tallow trees. For example, the insects that help keep tallow trees in check in Asia do not live in the U.S., and Siemann and his colleagues have found that the U.S. trees invest far less energy in producing chemicals that ward off insects. They've also found that U.S. trees grow about 30 percent faster than their Chinese kin.
In 2005, Siemann set out to gather genetic evidence that could help answer such questions. With funding from the National Science Foundation and the Department of Agriculture, he and study co-authors William Rogers, now at Texas A&M University, and Saara DeWalt, now at Clemson University, collected and froze leaves from more than 1,000 tallow trees at 51 sites in the U.S. and a dozen sites in China. The researchers conducted hundreds of genetic scans on the leaves, and they spent more than two years analyzing and correlating the results.
There were a few surprises. First, the tallow trees that are running amok in most of the U.S. aren't from the batch that Franklin imported. The descendants of Franklin's trees are confined to a few thousand square miles of coastal plain in northern Georgia and southern South Carolina. All other U.S. tallow trees the team sampled were descended from seeds brought to the U.S. by federal biologists around 1905.
"The genetic picture for Franklin's trees is muddled; we may never know where they originated," Siemann said. "But the genetic evidence for the other population -- the one that's problematic in the Gulf Coast -- clearly points to it being descended from eastern China, probably in the area around Shanghai."
In controlled tests in China, the researchers found the U.S. trees even grew and spread faster than their Chinese forebears, despite the lack of chemical defenses to ward off insects.
"They suffered twice the damage from insects that the natives did, but they grew so much faster that they still retained a competitive edge," Siemann said.
"In some ways, this raises even more questions, but it clearly shows that if you are going to explore control methods for an invasive species, you to need to use appropriate genetic material to make certain your tests are valid."
Siemann said that with many new species of plants and animals still being introduced from foreign environments into the U.S. each year, it is vitally important for scientists to better understand the circumstances that cause introduced species to cross the line and become dangerous invasive pests.
Jade Boyd | EurekAlert!
First time-lapse footage of cell activity during limb regeneration
25.10.2016 | eLife
Phenotype at the push of a button
25.10.2016 | Institut für Pflanzenbiochemie
Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.
This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...
Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion
Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
25.10.2016 | Earth Sciences
25.10.2016 | Power and Electrical Engineering
25.10.2016 | Process Engineering