GEOapplication/xmlftp://ftp.ncbi.nlm.nih.gov/geo/series/GSE328nnn/GSE328195/primaryOK200TranscriptomicsGallus gallusExpression profiling by high throughput sequencinghttps://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE328195GEOGSEfalseGene regulatory co-option drives birdsong neural circuit specialization [overexpression snRNA-Seq]As animals evolve more complex motor skills, they acquire more diverse supporting motor circuits in their nervous systems. Yet the molecular mechanisms driving motor circuit evolution remain poorly understood. Birdsong, a learned complex motor skill with parallels to human speech, is controlled by a dedicated neural circuit -- the song system -- that is distinguished from nearby sensorimotor regions by molecular, physiological, and connectivity specializations. By profiling gene expression and chromatin accessibility in the songbird brain, we have found that each projection neuron type in the song system has a molecularly similar sister neuron type in adjacent non-song regions that lacks specialized gene expression and is transcriptionally similar to neurons in the chicken brain. The GRNs controlled by transcription factors \textit{MAFB} and \textit{EMX2}, typically active in fast-spiking interneurons and astrocytes, are specifically active in song-dedicated extratelencephalic projection neurons. Furthermore, the heterologous expression of \textit{MAFB} or \textit{EMX2} in chicken projection neurons was sufficient to drive song neuron-like expression programs. These results support a model in which song-dedicated neurons emerged from ancestral neural types in part through the co-option of GRNs active in other cellular contexts, providing a genetic mechanism underlying the evolution of birdsong.2026/04/24GSE328195GSM9674804GSM9674803GSM967480235450328195Gallus gallus