Collaborative research: Genotypic and phenotypic changes associated with encephalization

这个研究小组正在阐明在人类祖先时期，大脑新皮层扩张的基因变化。这个跨学科的科学家团队编制了一份基因清单，这些基因对大脑的解剖发育或生化功能很重要。通过利用可公开获得的比较基因组序列数据，研究人员正在他们的大脑重要基因列表中识别那些显示人类祖先适应性变化证据的基因。研究人员打算找出这种适应性变化是否确实与脑化有关，脑化过程导致大脑皮层显著增大，认知能力增强。为了做到这一点，比较基因序列数据将扩大到包括其他灵长类动物和其他哺乳动物。选择的物种将允许测试这样一个假设，即那些在人类谱系中显示适应性变化的大脑重要基因，也将在脑化增加的非人类谱系中显示出比脑化没有增加的谱系更高的适应性变化频率。例如，研究人员将把脑容量大的瓶鼻海豚（Tursiops truncatus）与脑容量较小的齿状抹香鲸（Physeter macrocephalus）和神秘蓝鲸（Balaenoptera musculus）进行比较。除了基因数据外，还将收集其他类型的脑化分子数据。为此，研究人员将使用免疫组织化学技术来确定在猕猴、黑猩猩和人类中，特定的神经解剖结构是否显示出与有氧能量产生有关的基因活性水平的增加，这一结果将与人类谱系中新皮层的显著扩张有关。我们将为多种灵长类动物和其他哺乳动物建立一个新皮质表型特征数据库，以寻找表征认知能力增强的大脑出现的皮质组织学特征。更广泛的影响包括建立一个网站来传播这些区分脑化和非脑化谱系的基因型和表型数据。总的来说，这项工作将进一步实现我们的目标，即确定人类的遗传基础，并确定哪些基础是人类真正独特的。这个由灵长类动物学家、生化遗传学家、神经科学家和人类学家组成的跨学科团队，在不同学科之间架起了桥梁，以阐明塑造人类大脑的相关基因型-表型变化。通过对人类在自然界中的生物地位产生更客观的看法，这项研究应该具有广泛的社会影响。确定塑造人类大脑的基因变化可能被证明在寻找精神健康领域的新治疗药物方面具有重大价值。

This research team is elucidating the genetic changes that orchestrated the expansion of the brain's neocortex during humankind's ancestry. This interdisciplinary team of scientists has compiled a list of genes that are important for the brain's anatomical development or its biochemical functioning. By utilizing the comparative genomic sequence data that are publicly available, the investigators are identifying in their list of brain-important genes those showing evidence of adaptive change in humankind's ancestry. The investigators intend to find out if such adaptive change is indeed associated with encephalization, the process that brought about brains with marked neocortical enlargements and increased cognitive capacities. To do so, the comparative gene sequence data will be enlarged to include a selection of other primates and other mammals. The species selected will allow testing of the hypothesis that those brain-important genes showing adaptive change in the lineage to humans will also show a higher frequency of adaptive change in non-human lineages where encephalization increased than in lineages where encephalization did not increase. For example, the investigators will compare the encephalized bottle-nosed dolphin (Tursiops truncatus) to the less encephalized odontocete sperm whale (Physeter macrocephalus) and mysticete blue whale (Balaenoptera musculus). In addition to the gene data, other types of molecular data on encephalization will also be gathered. To this end, the investigators will use immunohistochemical techniques to determine whether particular neuroanatomical structures show increasing levels of activity for genes involved in aerobic energy production in the series of macaques, chimpanzees and humans, a result that would correlate with the marked expansion of the neocortex in the human lineage. A database of neocortical phenotypic features will be constructed for a diverse range of primates and other mammals in order to search for cortical histological features that characterize the emergence of brains with increased cognitive capacities. Broader impacts include the establishment of a web site to disseminate these genotypic and phenotypic data that distinguish encephalized from non-encephalized lineages. Taken together, this work will further our goal of identifying the genetic underpinnings of humankind and determining which of the underpinnings are truly unique for humans. The interdisciplinary team of primatologists, biochemical geneticists, neuroscientists and anthropologists bridges diverse disciplines in order to elucidate the linked genotypic-phenotypic changes that shaped the human brain. By yielding a more objective view of the biological place of humans in nature, this research should have broad societal impact. Identifying the genetic changes that shaped the human brain could prove to be of great value in the search for new therapeutic agents in the field of mental health.