Temporal changes in genetic variation during the invasion of Lygodium japonicum in North America
Premise of the study. Invasive species are now widespread and have detrimental ecological and economic impacts. They also offer opportunities to investigate rapid evolution in colonizing populations. Here, we leverage nuclear DNA from herbarium specimens of Lygodium japonicum, an invasive fern to 1) identify the putative source(s) of its invasion, 2) test for climate adaptation in its invaded…
Invasive fern species Lygodium japonicum has spread extensively across North America, causing ecological and economic harm. Researchers utilized herbarium specimens of L. japonicum dating back to 1905 to 2017 to investigate rapid genetic changes in the invasive population. Their study aimed to identify the source region of the invasion, assess if the invaders adapted to local climates, and analyze how genetic bottlenecks impacted both adaptive and neutral genetic variation during establishment.
By employing low-coverage genome skimming data, the researchers pinpointed mainland Asia as the most probable source region for the invasion. They identified 144 candidate single nucleotide polymorphisms (SNPs) significantly linked to climatic variation in the invaded range, with the driest month's precipitation exhibiting the strongest association. This suggests that L. japonicum experienced rapid genomic adaptation to the new environment.
Further analysis revealed conflicting trends in genetic diversity over time. In non-coding loci, there was a slight and statistically significant decrease in genetic diversity. However, within putatively adaptive loci, no evidence of a genetic bottleneck was found. These findings demonstrate that natural history collections can provide valuable insights into evolutionary processes by preserving genetic sequences across time, revealing evidence of rapid evolution, preservation of adaptive variation, and accumulation of noncoding diversity in the Lygodium japonicum invasion.
Written by urgent.news from bioRxiv's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.
