Phylogeography of Artemisia frigida (Anthemideae, Asteraceae) based on genotyping‐by‐sequencing and plastid DNA data: Migration through Beringia

• Published in: Journal of evolutionary biology Vol. 35; no. 1; pp. 64 - 80
• Main Authors: Oyundelger, Khurelpurev, Harpke, Dörte, Herklotz, Veit, Troeva, Elena, Zheng, Zhenzhen, Li, Zheng, Oyuntsetseg, Batlai, Wagner, Viktoria, Wesche, Karsten, Ritz, Christiane M.
• Format: Journal Article
• Language: English
• Published: Switzerland Blackwell Publishing Ltd 01.01.2022
• Subjects: Artemisia - genetics; Artemisia frigida; Bering land bridge; Climatic conditions; Diploids; Distribution patterns; DNA; DNA sequencing; GBS; Genetic distance; Genetic structure; Genetic Variation; Genotype; Genotyping; Geographical distribution; Grasslands; Humans; Land bridges; Phylogeny; Phylogeography; Plastids; Ploidy; Polyploidy; Populations; prairie sagewort; Sequence Analysis, DNA; Spacer region; Species; Asia; North America; GBS; prairie sagewort; Bering land bridge; phylogeography
• ISSN: 1010-061X; 1420-9101
• DOI: 10.1111/jeb.13960

Artemisia frigida is a temperate grassland species that has the largest natural range among its genus, with occurrences across the temperate grassland biomes of Eurasia and North America. Despite its wide geographic range, we know little about the species’ distribution history. Hence, we conducted a phylogeographical study to test the hypothesis that the species’ distribution pattern is related to a potential historical migration over the ‘Bering land bridge’. We applied two molecular approaches: genotyping‐by‐sequencing (GBS) and Sanger sequencing of the plastid intergenic spacer region (rpl32 – trnL) to investigate genetic differentiation and relatedness among 21 populations from North America, Middle Asia, Central Asia and the Russian Far East. Furthermore, we identified the ploidy level of individuals based on GBS data. Our results indicate that A. frigida originated in Asia, spread northwards to the Far East and then to North America across the Bering Strait. We found a pronounced genetic structuring between Middle and Central Asian populations with mixed ploidy levels, tetraploids in the Far East, and nearly exclusively diploids in North America except for one individual. According to phylogenetic analysis, two populations of Kazakhstan (KZ2 and KZ3) represent the most likely ancestral diploids that constitute the basally branching lineages, and subsequent polyploidization has occurred on several occasions independently. Mantel tests revealed weak correlations between genetic distance and geographical distance and climatic conditions, which indicates that paleoclimatic fluctuations may have more profoundly influenced A. frigida's spatial genetic structure and distribution than the current environment. Based on the extensive sampling across its distribution range, Artemisia frigida originated presumably in the Middle Asia and migrated through the Bering Strait. We found seven genetic clusters among the four geographical regions, with high genetic variability and mixed ploidy levels within Asia.