Wang Xin, Feng Qing-Hong, Zeng Zhi-Hua, Zhang Zhi-Qiang, Cai Jie, Chen Gao, Li De-Zhu, Wang Hong, Zhou Wei
Germplasm Bank of Wild Species & Yunnan Key Laboratory of Crop Wild Relatives Omics, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan 650201, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Plant Divers. 2024 Sep 25;47(1):136-147. doi: 10.1016/j.pld.2024.09.009. eCollection 2025 Jan.
Evolutionary transitions from sexual to asexual reproduction should have significant influences on genetic divergence and polymorphism at the genome level. Plant lineages with diverse reproductive systems provide opportunities to investigate this question using comparative approaches and studies of molecular evolution. We investigated evidence for differences among the transcriptomes of 19 species (wild yams) with diverse reproductive systems. These included sexual species, those that propagate primarily by bulbils, and those with mixed sexual and asexual reproductive modes. We examined how transitions between these reproductive systems affected between-species divergence and within-species polymorphism. Primarily asexual species exhibited a reduced efficacy of natural selection and accumulation of deleterious mutations for both divergence and polymorphism. In contrast, species with mixed reproductive strategies involving both seed and clonal reproduction showed no evidence of an increased fixation of harmful mutations at the divergence level, while an accumulation of genetic load present in polymorphism was evident. Our study indicates that the genetic consequences of evolutionary transitions from sexual to predominantly clonal reproduction is likely to depend on both the duration and extent of asexuality occurring in populations.
从有性繁殖到无性繁殖的进化转变应该会对基因组水平的遗传分化和多态性产生重大影响。具有不同繁殖系统的植物谱系为使用比较方法和分子进化研究来探究这个问题提供了机会。我们研究了19种具有不同繁殖系统的物种（野生山药）转录组之间差异的证据。这些物种包括有性物种、主要通过珠芽繁殖的物种以及具有有性和无性混合繁殖模式的物种。我们研究了这些繁殖系统之间的转变如何影响物种间的分化和种内多态性。主要为无性繁殖的物种在分化和多态性方面表现出自然选择效率降低和有害突变积累的现象。相比之下，涉及种子和克隆繁殖的混合繁殖策略的物种在分化水平上没有显示出有害突变固定增加的证据，而多态性中存在的遗传负荷积累则很明显。我们的研究表明，从有性繁殖到主要为克隆繁殖的进化转变的遗传后果可能取决于种群中无性繁殖发生的持续时间和程度。
