To date, the predicted major genetic component of autism spectrum disorders (ASD) has been explored using single nucleotide polymorphisms (SNPs) and copy number variations (CNVs) with success in finding the cause of a small minority of ASD cases. Here, researchers add another form of genome variation, retrotransposon-induced polymorphisms (RIPs), to the search for ASD etiology. Retrotransposons are genetic elements that can amplify themselves in a genome and are an often-overlooked source of inter-individual genomic variation in mammals. Researchers in this study have developed a technique to locate retrotransposon insertions with good specificity and sensitivity by high-throughput sequencing, and have been using it to find human-specific insertions from various individuals. This new high-throughput technology will be used to examine whether retrotransposition plays a role in the genetic susceptibility to autism-spectrum disorders (ASDs).