IMPRS DOCTORAL DEFENCE: Gökberk Alagöz

This thesis investigates the genetic and molecular bases of human brain evolution, with a particular focus on the biological foundations of brain structure, reading, and musicality. By integrating approaches from neuroimaging genomics, behavioural genetics, evolutionary genomics, and primate brain spatial transcriptomics, this thesis aims to bridge the gap between the genome, brain structure, and complex behavioural traits. Using large-scale genetic and neuroimaging data sets, the thesis identifies novel associations between common genetic variants, and aspects of human neuroanatomy, including cortical surface area, white-matter connectivity, and sulcal morphology. The findings reveal intricate links between the genetic architecture of these traits, and evolutionary genomic elements, such as human-gained enhancers active in the foetal brain. Another chapter uses bivariate genome-wide analyses to uncover shared genetic substrates between dyslexia and musical rhythm impairment, providing empirical ground for debates over the co-evolution of language and musicality. Finally, by generating the first spatial transcriptomics data set from a chimpanzee brain, this work offers insights into the spatial gene activity and cellular organisation in the chimpanzee frontal pole, and lays groundwork for future cross-species comparisons. Together, these findings contribute to our understanding of the genetic and molecular evolution of the human brain, language, and musicality.