Defendini Hélène, Prunier-Leterme Nathalie, Robin Stéphanie, Lameiras Sonia, Baulande Sylvain, Simon Jean-Christophe, Jaquiéry Julie
UMR 1349, IGEPP, INRAE, Institut Agro, Université de Rennes, 35653 Le Rheu and 35000 Rennes, France.
Institut Curie, PSL University, ICGex Next-Generation Sequencing Platform, Paris 75005, France.
Proc Biol Sci. 2025 Jan;292(2039):20242631. doi: 10.1098/rspb.2024.2631. Epub 2025 Jan 29.
Sexual conflict can arise because males and females, while sharing most of their genome, can have different phenotypic optima. Sexually dimorphic gene expression may help reduce conflict, but the expression of many genes may remain sub-optimal owing to unresolved tensions between the sexes. Asexual lineages lack such conflict, making them relevant models for understanding the extent to which sexual conflict influences gene expression. We investigate the evolution of sexual conflict subsequent to sex loss by contrasting the gene expression patterns of sexual and asexual lineages in the pea aphid . Although asexual lineages of this aphid produce a small number of males in autumn, their mating opportunities are limited because of geographic isolation between sexual and asexual lineages. Therefore, gene expression in parthenogenetic females of asexual lineages is no longer constrained by that of other morphs. We found that the expression of genes in males from asexual lineages tended towards the parthenogenetic female optimum, in agreement with theoretical predictions. Surprisingly, males and parthenogenetic females of asexual lineages overexpressed genes normally found in the ovaries and testes of sexual morphs. These changes in gene expression in asexual lineages may arise from the relaxation of selection or the dysregulation of gene networks otherwise used in sexual lineages.
性冲突可能会出现，因为雄性和雌性虽然共享大部分基因组，但可能具有不同的表型最优值。两性异形的基因表达可能有助于减少冲突，但由于两性之间未解决的紧张关系，许多基因的表达可能仍未达到最优。无性谱系不存在这种冲突，这使其成为理解性冲突对基因表达影响程度的相关模型。我们通过对比豌豆蚜有性和无性谱系的基因表达模式，研究了性丧失后性冲突的演变。虽然这种蚜虫的无性谱系在秋季会产生少量雄性，但由于有性和无性谱系之间的地理隔离，它们的交配机会有限。因此，无性谱系孤雌生殖雌性的基因表达不再受到其他形态的限制。我们发现，无性谱系雄性的基因表达倾向于孤雌生殖雌性的最优值，这与理论预测一致。令人惊讶的是，无性谱系的雄性和孤雌生殖雌性过度表达了通常在有性形态的卵巢和睾丸中发现的基因。无性谱系中基因表达的这些变化可能源于选择压力的放松或在有性谱系中使用的基因网络的失调。
