Genome sequences and population genomics provide insights into the demographic history, inbreeding, and mutation load of two ‘living fossil’ tree species of Dipteronia

• DOI: 10.1111/tpj.16486
• Publication Date: 2023-10-06T17:26:24Z
• Authors: Yu Feng; Hans Peter Comes; Jun Chen; Shanshan Zhu; Ruisen Lu; Xinyi Zhang; Pan Li; Jie Qiu; Kenneth M. Olsen; Yingxiong Qiu
• Keywords: Demographic history; Genetic load; Effective population size; Population genomics; Genetic drift; Balancing selection

SUMMARY ‘Living fossils’, that is, ancient lineages of low taxonomic diversity, represent an exceptional evolutionary heritage, yet we know little about how demographic history and deleterious mutation load have affected their long‐term survival extinction risk. We performed whole‐genome sequencing population genomic analyses on Dipteronia sinensis D. dyeriana , two East Asian Tertiary relict trees. found large‐scale genome reorganizations identified species‐specific genes under positive selection are likely involved in adaptation. Our suggest the wider‐ranged repeatedly recovered from bottlenecks over late Tertiary/Quaternary periods adverse climate conditions, while size narrow‐ranged steadily decreased since Miocene, especially after Last Glacial Maximum (LGM). conclude efficient purging mutations facilitated its repeated recovery. By contrast, increased genetic drift reduced efficacy, due to recent severe a preponderance vegetative propagation, resulted fixation strongly mutations, fitness, continuous decline, with detrimental consequences for species' future viability adaptive potential. Overall, our findings highlight significant impact levels accumulation putatively determine risk