Mitochondrial DNA Haplotype Distribution Patterns in Pinus ponderosa (Pinaceae): Range-wide evolutionary history and implications for conservation
Potter KM, Hipkins VD, Mahalovich MF, Means RE. 2013. Mitochondrial DNA Haplotype Distribution Patterns in Pinus ponderosa (Pinaceae): Range-wide evolutionary history and implications for conservation. American Journal of Botany. 100(8)
Premise of the study: Ponderosa pine ( Pinus ponderosa Douglas ex P. Lawson & C. Lawson) exhibits complicated patterns of morphological and genetic variation across its range in western North America. This study aims to clarify P. ponderosa evolutionary history and phylogeography using a highly polymorphic mitochondrial DNA marker, with results offering insights into how geographical and climatological processes drove the modern evolutionary structure of tree species in the region. • Methods: We amplifi ed the mtDNA nad1 second intron minisatellite region for 3,100 trees representing 104 populations, and sequenced all length variants. We estimated population-level haplotypic diversity and determined diversity partitioning among varieties, races and populations. After aligning sequences of minisatellite repeat motifs, we evaluated evolutionary relationships among haplotypes. • Key results: The geographical structuring of the 10 haplotypes corresponded with division between Pacifi c and Rocky Mountain varieties. Pacifi c haplotypes clustered with high bootstrap support, and appear to have descended from Rocky Mountain haplotypes. A greater proportion of diversity was partitioned between Rocky Mountain races than between Pacifi c races. Areas of highest haplotypic diversity were the southern Sierra Nevada mountain range in California, northwestern California, and southern Nevada. • Conclusions: Pinus ponderosa haplotype distribution patterns suggest a complex phylogeographic history not revealed by other genetic and morphological data, or by the sparse paleoecological record. The results appear consistent with long-term divergence between the Pacifi c and Rocky Mountain varieties, along with more recent divergences not well-associated with race. Pleistocene refugia may have existed in areas of high haplotypic diversity, as well as the Great Basin, Southwestern United States/northern Mexico, and the High Plains.
- Type
- Journal Article
- Authors
- Potter, Kevin; Hipkins, Valerie; Mahalovich, Mary; Means, Robert
- Units
- BIHO , GLAC , LABE , LAVO , SEQU , YOSE
- Keywords
- Migration, minisatellite, Mitochondrial DNA, Phylogeography, Pinus ponderosa, Pinus washoensis, Pleistocene, polymorphism, Ponderosa Pine
- Subjects
- Ecological Framework: Biological Integrity | Focal Species or Communities | Forest/Woodland Communities