Climate change often forces animals and plants to migrate or face extinction. However, migration has triggered changes in the bellflower’s DNA.
In a study conducted at the University of Virginia and Washington State University, scientists have revealed that the colonisation of new environments after the last ice age has fundamentally altered the American bellflower’s DNA.
The bellflower or Campanulastrum americanum often inhabits moist woods and well shaded streams in Virginia, USA. Despite its common name, derived from the Latin campana, meaning bell, the flowers are usually flat and not bell shaped.
Laura Galloway, of the University of Virginia, is a professor of biology and also co-author of the study. Galloway said: “The plant is ideal for study because it expanded its range when the climate last warmed and glaciers retreated…We learned that migration causes evolution that is both beneficial – making it easier for plants to reproduce – and detrimental – reducing the success of that reproduction.”
By sequencing the genomes of American bellflowers from various geographical areas, researchers found patterns of genetic mutations. These patterns then help scientists to identify a location in what is now eastern Kentucky, in the foothills of the Appalachian Mountains, where the plant likely persisted during the last ice age.
The research also showed that the process of expansion to the species’ current habitats in the eastern United States involved repeated periods when populations were small and gradually increased through colonisation.
The research teams from the University of Virginia and Washington State University also found interesting mutations in some of the flowers’ genes. The flowers farthest from their area of origin have evolved to generate their own fertilizer. The flowers also accumulated mutation that can be harmful to the well-being of the species over time.
The research highlights: “The spatial pattern of derived alleles in the site frequency spectra of C. americana populations is consistent with expansion from a refugium in eastern Kentucky, in the foothills of the Appalachian Mountains.”