Data from: Drosophila FoxP mutants are deficient in operant self-learning

Intact function of the Forkhead Box P2 (FOXP2) gene is necessary for normal development of speech and language. This important role has recently been extended, first to other forms of vocal learning in animals and then also to other forms of motor learning. The homology in structure and in function among the FoxP gene members raises the possibility that the ancestral FoxP gene may have evolved as a crucial component of the neural circuitry mediating motor learning. Here we report that genetic manipulations of the single Drosophila orthologue, dFoxP, disrupt operant self-learning, a form of motor learning sharing several conceptually analogous features with language acquisition. Structural alterations of the dFoxP locus uncovered the role of dFoxP in operant self-learning and habit formation, as well as the dispensability of dFoxP for operant world-learning, in which no motor learning occurs. These manipulations also led to subtle alterations in the brain anatomy, including a reduced volume of the optic glomeruli. RNAi-mediated interference with dFoxP expression levels copied the behavioral phenotype of the mutant flies, even in the absence of mRNA degradation. Our results provide evidence that motor learning and language acquisition share a common ancestral trait still present in extant invertebrates, manifest in operant self-learning. This ‘deep’ homology probably traces back to before the split between vertebrate and invertebrate animals.叉头框P2（Forkhead Box P2，FOXP2）基因的完整功能是言语与语言正常发育的必要前提。该基因的重要作用近来得到拓展：首先被证实可介导动物的其他类型发声学习，后续又被发现参与多种运动学习过程。FoxP基因家族各成员在结构与功能上的同源性，提示祖先FoxP基因可能演化成为介导运动学习的神经环路中的关键组成部分。本研究对果蝇的单拷贝同源基因dFoxP开展遗传操作，结果显示其会破坏操作性自我学习——这是一类与语言习得在概念层面存在多项相似特征的运动学习形式。对dFoxP基因座的结构改造，不仅揭示了dFoxP在操作性自我学习与习惯形成中的功能，还证实dFoxP对于操作性环境学习并非必需——后者并不涉及运动学习过程。此类遗传操作还会导致果蝇大脑解剖结构出现细微改变，包括视觉肾小球体积减小。通过RNA干扰（RNA interference，RNAi）干预dFoxP的表达水平，即便未发生mRNA降解，也可复刻突变果蝇的行为表型。本研究结果提供了证据：运动学习与语言习得共享一个可追溯至现存无脊椎动物的共同祖先性状，该性状以操作性自我学习的形式呈现。这种“深度同源性”大概率可追溯至脊椎动物与无脊椎动物分化之前的演化阶段。