Gene-Culture interactions in the evolution of birdsong

孟加拉雀是白腹灰雀的驯化品种。驯化的过程可以追溯到大约240年前，当时野生白腰从中国南方进口到日本。虽然野生品种唱简单的线性歌曲交配吸引力，驯化的菌株唱复杂的歌曲，可以表达的有限状态自动机。我们假设，驯化放松了一些选择压力，包括觅食和捕食成本和性选择仍然是一个主要的选择压力的歌曲。因此，文化和遗传因素应该区分两个品系之间的歌曲。我们进行了野外和实验室工作来证明其中的一些假设。损毁孟加拉雀鸣唱控制核团的一部分导致了鸣唱的简化，这表明应该存在一些大脑机制来解释鸣唱的差异。为了探究歌曲学习的先天性程度，我们将白腰燕雀和孟加拉雀的幼鸟进行了交叉培养。为了检测鸣唱学习的先天偏好，我们建立了一个5,000个克隆的cDNA微阵列，发现了一些候选基因。基于阵列分析，我们进行了原位杂交研究，以确定这些基因的脑分布。在基底节的NMDA受体亚型和Arcopallium的PKC亚型中发现了差异。虽然这些基因的功能贡献的歌曲的两个菌株，我们开始了解文化的影响，遗传组成。通过这些研究，我们希望能够阐明行为中基因-文化协同进化的机制。

Bengalese finches are domesticated strain of the white-romped munia. The process of domestication dates back some 240 years when wild white-rumped munias were imported to Japan from South China. Although the wild strain sings simple linear song for mate attraction, the domesticated strain sings complex songs that could be expressed by finite-state automata. We hypothesized that domestication relaxed some of the selection pressures including foraging and predation costs and sexual selection remained as a main selection pressure for song. Thus cultural and genetic factors should differentiate the songs between the two strains. We performed field and laboratory works to prove some of these hypotheses.Lesioning a part of song control nuclei in Bengalese finches resulted in simplification of the song, suggesting that there should be some brain mechanisms that account for the differences in songs. To ask the degree of innateness in song learning, we cross-fostered chicks of white-rumped munias and Bengalese finches. Some of rapid frequency modulations and complex syntax structures were not learned by the cross-fostered white-rumped munias, suggesting the existence of innate bias for song learning.To detect genes responsible for the innate bias for song learning, we developed a 5,000-clone cDNA microarray and found some candidate genes. Based on the array analyses, we performed in-situ hybridization studies to identify brain distribution of these genes. Differences were found in a sub-type of the NMDA receptor in basal ganglia and a sub-type of the PKC in arcopallium. Although functional contribution of these genes in songs of the two strains, we began to understand the cultural influence of genetic compositions. Through these researches we hope to clarify the mechanisms of gene-culture co-evolution in behavior.