Transcriptional Basis of Neuronal Diversity in the Mammalian Brain

Neuronal diversity is a defining feature of the mammalian brain deemed necessary for realizing the complex function of the nervous system. In order to begin to understand the transcriptional basis of this diversity, we collected more than 170 neuronal and non-neuronal cell type-specific transcriptomes defined operationally by transgenic mouse lines and anatomical regions. The dataset indicates that the genes specifically expressed in neuronal cell types are biased toward long genes. We revealed that these long genes have higher capacities to be differentially expressed between cell types and thus assume an important role in diversification of the neuronal transcriptomes. Since mobile element insertions are the main cause of the gene elongations, we propose that exaptation of the inserted mobile elements significantly contributed to the neuronal diversity. Examination of whole cell transcriptomes in 174 cell types.