Graduate School of Life Sciences, Tohoku University, Sendai, Japan.
Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala Biomedical Centre, Sweden.
Genome Biol Evol. 2020 Oct 1;12(10):1918-1928. doi: 10.1093/gbe/evaa158.
Domestication has resulted in immense phenotypic changes in animals despite their relatively short evolutionary history. The European rabbit is one of the most recently domesticated animals, but exhibits distinct morphological, physiological, and behavioral differences from their wild conspecifics. A previous study revealed that sequence variants with striking allele frequency differences between wild and domestic rabbits were enriched in conserved noncoding regions, in the vicinity of genes involved in nervous system development. This suggests that a large proportion of the genetic changes targeted by selection during domestication might affect gene regulation. Here, we generated RNA-sequencing data for four brain regions (amygdala, hypothalamus, hippocampus, and parietal/temporal cortex) sampled at birth and revealed hundreds of differentially expressed genes (DEGs) between wild and domestic rabbits. DEGs in amygdala were significantly enriched for genes associated with dopaminergic function and all 12 DEGs in this category showed higher expression in domestic rabbits. DEGs in hippocampus were enriched for genes associated with ciliary function, all 21 genes in this category showed lower expression in domestic rabbits. These results indicate an important role of dopamine signaling and ciliary function in the evolution of tameness during rabbit domestication. Our study shows that gene expression in specific pathways has been profoundly altered during domestication, but that the majority of genes showing differential expression in this study have not been the direct targets of selection.
尽管动物的进化历史相对较短，但驯化导致了它们在表型上发生了巨大的变化。欧洲兔是最近被驯化的动物之一，但与野生同类相比，它们表现出明显的形态、生理和行为差异。之前的一项研究表明，在野生和家养兔子之间存在显著等位基因频率差异的序列变异在参与神经系统发育的基因附近的保守非编码区域中富集，这表明在驯化过程中选择所针对的遗传变化的很大一部分可能会影响基因调控。在这里，我们生成了四个脑区（杏仁核、下丘脑、海马体和顶颞叶皮质）在出生时采样的 RNA-seq 数据，并揭示了野生和家养兔子之间数百个差异表达基因 (DEG)。杏仁核中的 DEG 显著富集了与多巴胺能功能相关的基因，该类别中的所有 12 个 DEG 在家养兔子中表达更高。海马体中的 DEG 富集了与纤毛功能相关的基因，该类别中的所有 21 个基因在家养兔子中表达更低。这些结果表明多巴胺信号和纤毛功能在兔子驯化过程中温顺性的进化中起着重要作用。我们的研究表明，在驯化过程中，特定途径的基因表达发生了深刻的改变，但在这项研究中表现出差异表达的大多数基因并不是直接的选择目标。
