Can a road-trip across eastern North America, ancient ice sheets, and DNA samples unlock the ancestral history of jack pine trees? Julie Godbout and colleagues from the Universit Laval, Quebec, Canada, certainly hoped that driving across northeastern U.S. and Canada to collect samples from jack pine trees would shed some light on how glaciers may have impacted present-day pine genetics.
About 20,000 years ago, ice sheets covered most of the northern terrestrial surface of the continent of North America. For some boreal species this Last Glacial Maximum period may have profoundly influenced their present-day distribution and genetic diversity. Glaciers may have separated populations into isolated pockets and/or created barriers to dispersal and therefore gene flow.
In the November issue of the American Journal of Botany (http://www.amjbot.org/cgi/reprint/97/11/1903), Godbout and colleagues examined the genetic structure of jack pine (Pinus banksiana), one of the dominant tree species in the North American boreal forest, to see if they could determine its geographic history since the Last Glacial Maximum. In previous studies they had discovered that populations of jack pine from central and western Canada were genetically distinct from eastern populations. Moreover, the eastern populations were genetically quite diverse and heterogeneous, much more so than the central and western groups. Why was this?
"This study follows up a first rangewide phylogeographical work on jack pine that set us thinking that populations from the Maritimes region [New Brunswick, Nova Scotia, and Prince Edward Island] were genetically distinct from the rest," Godbout stated.
On their road trip across New England and the Maritimes provinces the authors completed their sampling of 1240 jack pine trees in 83 populations, collecting pine needles and young seedlings. Pine s
|Contact: Richard Hund|
American Journal of Botany