Molecular control mechanism of left-right asymmetry of flounders

比目鱼幼虫在变形时通过移动一只眼睛从对称形状转变为不对称形状。最终形态分为左旋种（如olivaceus）和右旋种（如Varasper veriegatus）。阐明了比目鱼侧眼发育控制系统。眼球迁移与前脑和头盖骨的动态不对称形成协调进行。结通路的最后一个L-R决定基因pitx2是控制内脏侧边性的基因，它在比目鱼的背间脑左侧表达，使眼侧边偏侧。当pitx2表达被抑制时，哪只眼的迁移是随机的，导致部分幼虫的眼侧性逆转。牙鲆分为左颌和右颌两种的机制与视交叉侧度在两种间沿相反方向固定密切相关。

Flounder larvae transform from symmetric to asymmetry shape by moving one eye at metamorphosis. Final shape is divided to sinistral species (e.g. Paralichthys olivaceus) and dextral species (e.g. Varasper veriegatus). We have elucidated the developmental control system of eye-sidedness of flounders. Eye migration proceeds in coordination with dynamic asymmetric formation of forebrain and cranium. Final L-R determinant gene, pitx2, of the Nodal pathway, known to control the laterality of internal organs, is expressed in the left side of dorsal diencephalon in flounders to lateralize the eye-sidedness. When pitx2 expression is suppressed, which eye migrates is randomized, resulting in reversal of eye-sidedness in part of larvae. The mechanism that divides flounders to sinistral and dextral species has close relation with the fact that the laterality of the optic chiasma is fixed in opposite direction between two species.