Furthermore, DSCAM is thought to have a role in 'tiling' during the drosophila's neuronal development. Tiling is a mechanism in which the processes from cells that share the same function work to create nerve bundles in a defined territory to create a pattern of non-overlapping dendritic or axonal fields. Dscam1 and Dscam2 appear to be involved in axonal branching and tiling in Drosophila. Tiling occurs when homophilic repulsion mediated by Dscam2 prevents the processes of the same class of cells from overlapping. While both Dscam1 and Dscam2 mediate homophilic repulsion, the Dscam2 gene (unlike Dscam1) only encodes two alternative isoforms and thus lacks possible molecular diversity. Consequently, the role of Dscam2, in either self-avoidance or cell-type-specific avoidance, occurs depending on which isoform or ratio of isoforms that the neuron expresses.