A University of Colorado Denver-led research team for the first time developed reliable genetic markers known as nuclear microsatellites for the whitebark pine, a discovery that could improve the tree’s prospects for survival. The whitebark pine is declining rapidly nearly range-wide as a result of climate change, which is why it is a candidate for listing under the Endangered Species Act.

First to succeed at genetic markers

According to a research article published in the academic journal PLOS ONE, “Development of nuclear microsatellite loci for Pinus albicaulis Engelm. (Pinaceae), a conifer of conservation concern,” the new genetic markers represent a useful and low-cost method for screening whitebark pine trees for levels of genetic variation.

Prior attempts to find these genetic markers were unsuccessful, thwarted by the complex, large and highly repetitive whitebark pine species genome, which is nearly nine times larger than the human genome.

Tool for whitebark conservation amid climate change

“With this breakthrough, scientists can begin screening whitebark pines for disease resistance traits, for strategic seed collection and other conservation and climate change mitigation efforts,” said Diana Tomback, PhD, a professor in the Department of Integrative Biology at CU Denver. “Genetic screening using microsatellites is a fast, affordable tool with multiple research and restoration applications for protecting this special tree, which plays a significant ecological role in high-mountain ecosystems.”

Whitebark pines from Yellowstone

The research team selected trees from the Greater Yellowstone Ecosystem for genetic screening, importantly, to align with ongoing studies of climate change in Yellowstone National Park and the surrounding region.

The imperiled high-altitude conifer ranges throughout the Western U.S. and Canada, and the species is important because it provides watershed protection and food for wildlife, including Grizzly Bears. Threats to the whitebark pine are linked to climate change. For example, challenges include non-native disease, mountain pine beetles, severe fire and drought. When large numbers of trees die, the result is a decline in genetic diversity of remaining whitebark populations.

A team effort

Tomback and CU Denver graduate student Marian Lea led the research team that succeeded in developing 23 microsatellite markers for whitebark pine, including 10 that are newly developed and 13 that were transferred from other pine species.

Research team members: Dr. John Syring (Professor, Linfield College, OR), and Dr. Richard Cronn and Tara Jennings (U.S. Forest Service Pacific Northwest Research Station) initiated this work by applying genome sequencing methods to the whitebark pine genome and identifying over 1,000 candidate gene regions for analysis. Dr. Leo Bruederle and Dr. Jennifer Neale (Denver Botanic Gardens) provided lab techniques that converted these regions into simple genetic assays. Lea, Syring, and Jennings performed detailed screening of the novel and transferred markers, and Lea completed the population analysis of two Yellowstone whitebark populations, which provided evidence that the markers were successful.