Abstract Detail

Biogeography

Cameron, Kenneth [1], Wang, Shenyi [2].

Phylogeography of Streptopus lanceolatus (Liliaceae): a North American endemic with a curious pattern of disjunction among the Pacific Northwest, Upper Midwest, and Eastern Appalachia.

Streptopus lanceolatus is a North American species that exhibits an inter-continental disjunction among the Pacific Northwestern, Upper Midwest and Eastern North America (especially along the Appalachian Mountains). This present disjunction might be the result of different patterns of evolutionary history and migration that were affected by glacial periods, especially during the Last Glacial Maximum (LGM). A phylogeographic study of S. lanceolatus across its entire range was conducted to elucidate the patterns and processes that underlie its pre-glacial history and present distribution. We applied Genotyping by Sequencing (GBS) to call Single Nucleotide Polymorphisms (SNPs) for 296 individuals from 62 populations to investigate their genetic diversity and population structure. All methods of analysis confirmed with strong support the presence of three distinct genetic clusters corresponding to the primary areas of present distribution: northwestern North America, the Upper Midwest, and eastern NorthAmerica. The western North American populations have the highest genetic diversity followed by Eastern North America then the Upper Midwest. And the Eastern populations (eastern North America and Upper Midwest) followed a significant Isolation by Distance (IBD) pattern. Evidence of gene flow between individuals from the Midwestern and Eastern populations was documented in glaciated areas of the northern Great Lakes, suggesting that these plants have been migrating northward from at least three different allopatric glacial refugia. The results support a hypothesis that the ancestor of S. lanceolatus firstly colonized far northwestern areas of North America from east Asia, spread eastward across the continent, and then survived in at least three different glacial refugia during the LGM after population restriction. Although we cannot exactly pinpoint where these refugia may have existed, the southernmost areas of the Pacific Northwest, southern Appalachians and Driftless Area of SW Wisconsin are suggested. These areas may have served as population sinks during the LGM, today are sources of unique genotypes, and could become important again as future refugia for thermophobic plant species under threat by climate change.

1 - University Of Wisconsin, Department Of Botany, 154 Birge Hall, 450 Lincoln Drive, Madison, WI, 53706, United States
2 - University of Wisconsin-Madison, Botany

Keywords:
Glaciation
Monocots
Liliales
Regugia
GBS
Driftless Area
Phylogeography.

Presentation Type: Oral Paper
Number: BIOG I004
Abstract ID:168
Candidate for Awards:None