Sexually dimorphic gene expression in the chick brain at stage 29

Biological bases for sexual differences in the brain exist in a wide range of vertebrate species, including the chicken. We examined whether sexually dimorphic gene expression in the brain precedes gonadal differentiation. Using the Affymetrix GeneChip® Chicken Genome Array, we identified many female- and male-enhanced genes that are differentially expressed in sex-specific brains from stage 29 chicken embryos. We postulate that these genes have potential roles in the sexual differentiation of neural function and development in chickens. All analyses were performed in triplicate. The Affymetrix data from male and female brain samples at stage 29 were generated. The male and female brain samples by genetic sexing were pooled and homogenized. Pooled samples ranged from 5 to 8 embryos. 4g of total RNA from the pooled samples was used for labeling. Probe synthesis from total RNA samples, hybridization, detection, and scanning were performed according to standard protocols from Affymetrix.