Invertebrate Models Of Synaptic Transmission In Autism Spectrum Disorders

The study of autism spectrum disorder (ASD) is difficult because of the heterogeneous phenotypic manifestation of the disease and because of the complexity of its etiology. The estimated genetic heritability of ASD is high, about 80 %. The identification of individual genes involved in this syndrome is essential for advancing in the understanding of the mechanisms involved in the development of the disease. Until now, more than 600 genes have been reported in human that could be related to ASDs, and over 70 % of them are orthologs to genes present in the genome of invertebrate animal models. This particular scenario is where invertebrate animals acquire special relevance as biological models, given the relative simplicity of their nervous system compared it to that of mammals. Moreover, many of the molecular mechanisms operating in neuronal synapses are evolutionarily conserved among vertebrates and invertebrates. Invertebrates are also easy to handle, and most of them are reproduced rapidly in the laboratory, which allows obtaining many individuals to study the effect of mutations and/or environmental factors in behavior. In this chapter, we review the features that make Drosophila melanogaster, Aplysia californica, and Caenorhabditis elegans exceptional models for the study of particular genes related to ASDs. We present some examples of the functional analysis of genes associated with these disorders in these organisms and discuss molecular basis of behaviors that might be significant in the etiology of ASDs.