Developmental changes within the genetic architecture of social communication behaviour: A multivariate study of genetic variance in unrelated individuals Short title: A multivariate study of genetic variance in unrelateds

1 Language and Genetics Department, Max Planck Institute for Psycholinguistics, The Netherlands 2 MRC Integrative Epidemiology Unit (MRC IEU), University of Bristol, UK 3 Donders Institute for Brain, Cognition and Behaviour, Radboud University, The Netherlands 4 Department of Human and Molecular Genetics, Institute for Psychiatric and Behavioral Genetics, Commonwealth University School of Medicine, Richmond, Virginia, USA 5 School of Social and Community Medicine, University of Bristol, UK 6 Psychiatric Genetics, QIMR Berghofer Medical Research Institute, Queensland, Australia 7 University of Queensland Diamantina Institute, Translational Research Institute, University of Queensland, Queensland, Australia