Yant, Levi
- Department of Plant Biology, Swedish University of Agricultural Sciences
- Charles University
- University of Nottingham
Abstract
Genetic variation underpins evolutionary change, but mutation accumulation increasesgenetic load. Various factors affect the extent of load, such as population size andbreeding system, but other important determinants remain unexplored. In particular,whole- genome duplication (WGD)—a pervasive macromutation occurring broadlyacross Eukaryotes—remains poorly understood in terms of its impact on neutral andselective processes within populations. Using iterative forward simulations and empiricalanalysis of 632 short- and 16 long-read sequenced individuals of Arabidopsis arenosa (in23 diploid and 42 natural autotetraploid populations), we measure the effects of WGDon genome-wide diversity and mutation load. Our simulations show how genetic varia-tion gradually rises in autotetraploids due to increased mutational target size. Moreover,mutation load increases due to relaxed purifying selection as ploidies rise, when delete-rious mutations are masked by additional chromosome copies. Empirical data confirmthese patterns, showing significant increases in nucleotide diversity, ratios of nonsyn-onymous to synonymous SNPs, and numbers of indels and large structural variants inA. arenosa autotetraploids. However, a rather modest increase in load proxies togetherwith a broad distribution and niche of autotetraploids suggests load accumulation hasnot yet limited their successful expansion. Overall, we demonstrate a complex interplaybetween neutral processes and purifying selection in shaping genetic variation followingWGD and highlight ploidy as an important determinant of mutation load, geneticdiversity, and therefore adaptive potential in natural populations.
Keywords
Arabidopsis; evolution; genomics; genetic load; natural selection
Published in
Proceedings of the National Academy of Sciences of the United States of America
2025, volume: 122, number: 31, article number: e2501739122
SLU Authors
UKÄ Subject classification
Evolutionary Biology
Genetics and Genomics
Publication identifier
- DOI: https://doi.org/10.1073/pnas.2501739122
Permanent link to this page (URI)
https://res.slu.se/id/publ/143228