2026-10-13 北海道大学
4魚種を用いた脳の左右差の比較解析のイメージ 本研究では、系統的に離れた4魚種を対象に、左脳と右脳に特化して発現する遺伝子を探索した。中央のDNAは、脳の左右差が進化的に保存された分子基盤に支えられていることを模式的に示す。
＜関連情報＞
- https://www.hokudai.ac.jp/news/2026/10/4-50.html
- https://www.cell.com/iscience/fulltext/S2589-0042(26)03239-6
種横断的RNAシーケンシングにより同定された、真骨魚類における脳の左右差遺伝子 Cross-species RNA sequencing identifies candidate lateralized genes in teleost brains
Yuichi Takeuchi ∙ Chika Fujimori ∙ Satoshi Ansai ∙ Jun Kitano
iScience Published:October 9, 2026
DOI:https://doi.org/10.1016/j.isci.2026.117858
Highlights
- Cross-species RNA-seq reveals shared patterns of brain asymmetry in teleosts
- Five candidate genes show consistent directional asymmetry across four fish species
- ddc and ntn1b are repeatedly left-biased in the teleost hindbrain
- ddc-expressing cells are more abundant in the left medaka raphe nuclei
Summary
Brain lateralization is widespread across vertebrates and contributes to hemispheric specialization. We compared left-right gene expression in the telencephalon and hindbrain of four phylogenetically distant teleosts: zebrafish, medaka, stickleback, and cichlid. Cross-species RNA sequencing identified five candidate genes with consistent directional expression biases. Although no genes remained significant after within-species FDR correction, Fisher’s combined probability test supported directional asymmetry of five candidate genes. Notably, ddc and ntn1b were more highly expressed in the left hindbrain in three species and showed similar trends in the remaining species. GO analysis revealed shared functional categories associated with lateralized expression, including transport-related functions in the right-biased telencephalon and nervous system and developmental functions in the left-biased hindbrain. In situ HCR showed more ddc-expressing cells in the left median and dorsal raphe nuclei of medaka. These findings identify candidate molecular signatures associated with shared patterns of brain asymmetry across phylogenetically distant teleosts.
