More than a century after two introduced pathogens killed billions of American chestnut trees, introgression of resistance alleles from Chinese chestnuts has contributed to the recovery of self-sustai...

We are seeking a highly motivated Post-Doctoral Research Fellow to join our research team at Reading, focusing on sedimentary DNA (sedaDNA / environmental DNA) from soils and sediments from the project’s case study regions in Spain and North Africa. You will contribute to the reconstruction of past landscapes and human-environment interactions through the analysis of sedimentary DNA. This includes analysing samples from terraces, irrigated fields and archaeological sites, and using eDNA metagenomics and metabarcoding approaches for multi-species detection, with the aim of characterising changing plant and animal species diversity and richness over time. The position will involve fieldwork, laboratory work, data analysis, and collaboration with an interdisciplinary team of archaeologists, palaeoecologists and historians.

Amphioxus are small marine chordates that have broad ecological ranges, yet as adults form local settlements and exhibit limited mobility. Genomic surveys of two amphioxus species have suggested that they rank among the most genetically diverse metazoans. Here, we present the first accurate assessment of genomic diversity in the European amphioxus ( Branchiostoma lanceolatum ) and investigate the processes underlying this diversity. We leverage high-coverage whole-genome sequencing data from multiple individuals sampled at two geographically distant Atlantic and Mediterranean locations. Consistent with previous estimates in other amphioxus species, we measure exceptionally high genomic diversity, with an average heterozygosity of 2.73% in B. lanceolatum . Despite the large geographic separation between sampling sites, population differentiation is minimal, indicating extensive gene flow among distant adult settlements. Phylogenetic analyses combined with population genetic simulations confirm that this elevated genomic diversity is primarily driven by a large effective population size. Although adult amphioxus have limited mobility, our results indicate that long-distance larval dispersal mediated by ocean currents is sufficient to generate a near-panmictic population structure across their broad ecological range. ### Competing Interest Statement The authors have declared no competing interest. Swiss National Science Foundation, 207853 Agence Nationale de la Recherche, ANR-21-CE13-0034