Classic case

Title: 

Long-distance pollen dispersal during recent colonization favors a rapid but partial recovery of genetic diversity in Picea sitchensis.
 
Journal:

New Phytologist (IF = 10.151)
 
Key findings:

(1) Tree species in the northern hemisphere are currently subject to rapid anthropogenic
climate change and are shifting their ranges in response. This prompts questions about the
mechanisms allowing tree populations to respond quickly to selection pressures when establishing
into new areas. Focusing on the northern expanding range edge of Picea sitchensis, a
widespread conifer of western North America, we ask how genetic structure and diversity
develop during colonization, and assess the role of demographic history in shaping the evolutionary
trajectory of an establishing population.

(2) We combined 500 yr of tree-ring and genotyping-by-sequencing data in 639 trees at the
expansion front on the Kodiak Archipelago.

(3) We show that alleles accumulated rapidly during an increase in recruitment rate in the early
1700s. A shift from foreign to local pollen flow subsequently homogenized genetic structure
at the expansion front.

(4) Taking advantage of the exceptional longevity of conifers, we highlight the major role of
long-distance pollen dispersal in the rapid but incomplete recovery of genetic diversity during
the initial stages of colonization. We also warn that slow initial population growth as well as
long-lasting dominance of local gene flow by early founders could increase evolutionary load
under a rapidly changing climate.

 

Publication

Joane S, Elleouet, Sally N et al. Long-distance pollen dispersal during recent colonization favors a rapid but partial recovery of genetic diversity in Picea sitchensis. The New Phytologist, 2018.