Evolutionary legacy of the “living fossil” genus Parrotia (Hamamelidaceae): genomic insights into species divergence and polygenic adaptation

作者：Yunyan Zhang, Kui Li, Yu Feng, Zhiyuan Li, Yimin Hu, Hamed Yousefzadeh, Malek Nasiri, Benjamin Adroit, Pengfu Li, Shan Lu, Li Pan, Hong Liu, Ye Peng, Chi Xu, Yingxiong Qiu, Zhongsheng Wang · 发表于：The Plant Journal · 年份：2025 · DOI：10.1111/tpj.70367 · 被引用次数：7 · 研究领域：Genomics and Phylogenetic Studies、Plant Diversity and Evolution、Chromosomal and Genetic Variations

Despite their long evolutionary history, the genomic basis of adaptation and speciation in "living fossil" plants remain largely unexplored. Parrotia, a Tertiary relict tree genus with two extant species, P. subaequalis and P. persica, exhibits a disjunct distribution between East Asia and West Asia. Here, we present the first chromosome-level assemblies for both species, confirmed their sibling relationship, and dated the speciation event to the early Miocene. The recent proliferation of long-terminal repeat retrotransposons has driven the genome expansion in P. subaequalis. We detected widespread heterogeneous genomic differentiation between species. Extensive signals of divergent selection, local adaptation, and elevated Ka/Ks ratios in Parrotia indicate that this genus has undergone adaptive evolution in distinct refugia, challenging the notion of it as an "evolutionary dead end". Our findings provide new insights into the genomic evolution, environmental adaptation, and speciation of this "living fossil" tree genus.