ABSTRACT
Adaptation is the central feature and leading explanation for the evolutionary diversification of life. Adaptation is also notoriously difficult to study in nature, owing to its complexity and logistically prohibitive timescale. We leverage extensive contemporary and historical collections of Ambrosia artemisiifolia—an aggressively invasive weed and primary cause of pollen-induced hayfever—to track the phenotypic and genetic causes of recent local adaptation across its native and invasive ranges in North America and Europe, respectively. Large haploblocks— indicative of chromosomal inversions—contain a disproportionate share (26%) of genomic regions conferring parallel adaptation to local climates between ranges, are associated with rapidly adapting traits, and exhibit dramatic frequency shifts over space and time. These results highlight the importance of large-effect standing variants in rapid adaptation, which have been critical to A. artemisiifolia’s global spread across vast climatic gradients.
Competing Interest Statement
The authors have declared no competing interest.
Footnotes
↵These authors jointly supervised this work: Kathryn A. Hodgins, Michael D. Martin
Assembled a new chromosome-level phased diploid Ambrosia artemisiifolia reference genome. Repeated all population-genomic analyses with samples aligned to one haplotype of this new reference. Identified eight additional haploblocks. Used an alignment of the two haplotypes in our diploid assembly to validate four haploblocks segregating in the reference. Added Fay & Wu's H scans for each modern population in historic-modern population pairs to support selective sweep analyses in these populations.
https://www.dropbox.com/s/98qy9bokn28z1vh/ragweed-natcomms-suptables.xlsx?dl=0
