Abstract Detail

Population Genetics

Martin, Michael D. [1], Olsen, Morten Tange [2], Samaniego, Jose A. [3], Zimmer, Elizabeth [4], Gilbert, M. Thomas P. [3].

The population genomic basis of geographic differentiation in North American common ragweed (Ambrosia artemisiifolia L.).

Ambrosia artemisiifolia is an invasive pioneer weed nearly ubiquitous in disturbed sites in its native range of eastern North America and present in growing a growing range of locales in Western and Eastern Europe, Africa, Asia and Australia. Containing one of the most potent natural allergens known, ragweed’s wind-dispersed pollen represents a threat to public health wherever it blows. Although widely distributed today, paleo-records from sediment cores of North American lakes indicate that the species was relatively uncommon before disturbance and eventual transformation of the landscape by European and American agriculture. A recent study used microsatellite loci and chloroplast SNP data from both modern populations and historical herbarium collections to show that this native range disturbance was associated with a large-scale shift in the genetic structure of this species before it was introduced to novel ranges abroad. While such structure is intriguing in itself, the environmental factors and genomic adaptations that potentially influence this structure have not yet been identified, and it remains unclear whether inter-population admixture during historical landscape disturbance contributed to the accelerated growth and other invasive characteristics of introduced European ragweed populations. Here we applied the Genotyping-by-Sequencing (GBS) genome reduction method to investigate fine-scale genetics of modern common ragweed populations across their native range. We used the UNEAK pipeline within the software TASSEL to cope with a large SNP dataset in this non-model organism, which lacks a reference genome. Through phylogeogenetic and population genetic analyses of approximately 6,000 biallelic SNP loci, we confirm the phylogeographic domains detailed in the previous study while further segmenting the Western genetic cluster into two domains inside and outside of Florida. Analyzing non-synonymous exome polymorphisms that correlate with the phylogeographic pattern, we identify Gene Ontology (GO) categories likely associated with adaptation of common ragweed populations to different locales in eastern North America.

1 - University Museum, Department of Natural History, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
2 - University of Copenhagen, Centre for GeoGenetics, Natural History Museum of Denmark, Øster Voldgade 5-7, Copenhagen, Denmark
3 - University of Copenhagen, Centre for GeoGenetics, Øster Voldgade 5-7, Copenhagen, Denmark
4 - Smithsonian Institution, National Museum of Natural History, Department of Botany, PO Box 37012, Washington, DC, 20013-7012

Keywords:
common ragweed
ragweed
population genetics
population genomics
Genotyping by sequencing (GBS).

Presentation Type: Poster
Session: P, Population Genetics Posters
Location: Exhibit Hall/Savannah International Trade and Convention Center
Date: Monday, August 1st, 2016
Time: 5:30 PM This poster will be presented at 6:15 pm. The Poster Session runs from 5:30 pm to 7:00 pm. Posters with odd poster numbers are presented at 5:30 pm, and posters with even poster numbers are presented at 6:15 pm.
Number: PPG006
Abstract ID:459
Candidate for Awards:None