Rapid Evolution Helps Spread of Exotic Plants

Researchers have just discovered the first genetic evidence that demonstrates how rapid evolution can help spread non-native plant species throughout new environments. With samples of centuries-old herbaria and DNA analysis, Belgium study authors were able to reconstruct genetic adaptations made by the Pyrenean rocket before it hit Belgium.

This plant is typical to the mountains of southern Europe, and was first reported in Belgium during the first half of the 19^th century at 1,200 kilometers north of its native range.

The colonization of this plant is easily documented, according to postdoctoral researchers and corresponding author Katrien Vandepitte. The Pyrenean rocket took hold on the River Vesdre in Verviers and later spread through the Meuse basin near the Netherlands.

 "We found dried specimens of the Pyrenean rocket in herbaria from the 19th and 20th centuries and were able to isolate DNA from these samples," she said, via a press release. "We then compared this DNA with the genetic profile of contemporary samples from Belgium and the Pyrenees. This gave us a unique opportunity to reconstruct when and how an exotic plant species genetically adapted to a new environment."

Further DNA examination of the Pyrenean rocket's genetic evolution showed a divergence of genes that regulate flowering, according to Vandepitte. 

"Our DNA analysis shows that the Belgian variant genetically adapted quite rapidly - in about 20 generations. This very likely helped the plant to survive and spread here."

"Our findings are important because until now evidence supporting the hypothesis that exotic plants can spread after a period of rapid genetic adaptation has been very scant," says Dr. Vandepitte.

The researchers' findings were published as the cover story in the May issue of the journal Molecular Ecology.