Institute of Organismic and Molecular Evolution, University of Mainz, 55128, Mainz, Germany.
Institute for Evolution and Biodiversity, University of Münster, 48161, Münster, Germany.
Commun Biol. 2024 May 16;7(1):581. doi: 10.1038/s42003-024-06266-7.
Many plants are facultatively asexual, balancing short-term benefits with long-term costs of asexuality. During range expansion, natural selection likely influences the genetic controls of asexuality in these organisms. However, evidence of natural selection driving asexuality is limited, and the evolutionary consequences of asexuality on the genomic and epigenomic diversity remain controversial. We analyzed population genomes and epigenomes of Spirodela polyrhiza, (L.) Schleid., a facultatively asexual plant that flowers rarely, revealing remarkably low genomic diversity and DNA methylation levels. Within species, demographic history and the frequency of asexual reproduction jointly determined intra-specific variations of genomic diversity and DNA methylation levels. Genome-wide scans revealed that genes associated with stress adaptations, flowering and embryogenesis were under positive selection. These data are consistent with the hypothesize that natural selection can shape the evolution of asexuality during habitat expansions, which alters genomic and epigenomic diversity levels.
许多植物是兼性无性的，在无性繁殖的短期利益和长期成本之间取得平衡。在范围扩张期间，自然选择可能会影响这些生物无性繁殖的遗传控制。然而，自然选择驱动无性繁殖的证据有限，无性繁殖对基因组和表观基因组多样性的进化后果仍然存在争议。我们分析了浮萍（Spirodela polyrhiza）（L.）Schleid.的种群基因组和表观基因组，这是一种兼性无性植物，很少开花，显示出非常低的基因组多样性和 DNA 甲基化水平。在种内，人口历史和无性繁殖的频率共同决定了基因组多样性和 DNA 甲基化水平的种内变异。全基因组扫描显示，与应激适应、开花和胚胎发生相关的基因受到正选择。这些数据与以下假设一致，即自然选择可以在生境扩张过程中塑造无性繁殖的进化，从而改变基因组和表观基因组多样性水平。
