Kin recognition: neurogenomic response to sib mating avoidance in a parasitic wasp. Kin recognition: neurogenomic response to sib mating avoidance in a parasitic wasp

Sib mating increase homozygosity and can lead to inbreeding depression. Selective pressures have favored the evolution of kin recognition and sib avoidance in mate choice. Such avoidance behavior has been recorded in the parasitoid wasp Venturia canescens where the sex determining system (single-locus complementary sex determination, sl-csd) introduces an extra short-term cost to inbreeding; females preferentially mate with unrelated males. The genetics underlying mate choice of females and kin recognition remains largely unexplored. Here we analyzed the head transcriptomic changes after exposure to distinct stimulus: courtship by unrelated male or courtship by brother, while transcriptome of females alone was used as control. Our results demonstrate that male courtship provokes a major transcriptome reprogramming in females heads. The transcriptomic response is highly dependent on the compatibility of the courting male. We subdivided the socially responsive genes using an integrative gene network analysis, we highlighted genes regulated by courtship, whatever the relatedness of the courting male. We also showed that the regulation of some peculiar group of genes is very specific of compatible male courtship, while others are regulated only by incompatible male courtship. We suggest that those different transcriptomic responses lead to mating decision or sib mating avoidance behavior observed in this species. Overall design: Venturia canescens females head transcriptome after 10 minutes : i) courtship by compatible male (unrelated); ii) courtship by incompatible male (brother); iii) isolated (control). X 3 biological replicates; X 2 technical replicates (18 RNAseq librairies)

同胞交配可提升个体纯合性，并可能引发近交衰退。自然选择压力推动了配偶选择过程中亲缘识别与同胞回避行为的演化。此类回避行为已在寄生蜂Venturia canescens中被观测到，其性别决定系统为单基因互补性别决定（single-locus complementary sex determination, sl-csd），该系统会为近交带来额外的短期成本；雌性蜂会优先选择与无亲缘关系的雄蜂交配。目前，雌性配偶选择与亲缘识别背后的遗传机制仍有待深入解析。
本研究分析了雌性个体暴露于不同求偶刺激后的头部转录组变化，刺激类型分别为无关雄蜂的求偶与同胞雄蜂的求偶，并以未受刺激的雌性头部转录组作为对照。研究结果表明，雄蜂的求偶行为会引发雌性头部转录组的大规模重编程，且转录组响应模式与求偶雄蜂的亲缘兼容性高度相关。我们通过整合基因网络分析对社会响应基因进行了分类：一方面筛选出了无论求偶雄蜂亲缘关系如何，均受求偶行为调控的基因；另一方面发现，部分特殊基因簇的调控仅特异性响应兼容性雄蜂的求偶刺激，而另一部分基因则仅在非兼容性雄蜂（即同胞雄蜂）的求偶刺激下被调控。我们推测，这些差异化的转录组响应正是该物种中观测到的交配决策与同胞回避行为的分子基础。
实验整体设计：对经过以下三种处理10分钟后的雌性Venturia canescens头部进行转录组测序：i）与无亲缘关系的兼容性雄蜂进行求偶互动；ii）与同胞雄蜂（非兼容性雄蜂）进行求偶互动；iii）单独隔离（空白对照）。每组设置3次生物学重复与2次技术重复，共计构建18个RNA测序文库。