Sex differences in gene expression of developing fetal brain in pig

In this study, gene expression was profiled by RNA-seq to examine whole transcriptome of the male and female fetal brain of domesticated pig on the three gestation days 45, 60 and 90. Gene expression in fetal brain was distinct on day 90 compared to days 45 and 60. The homeobox genes were consistently upregulated in the brain of females compared to males during development. The sex of adjacent fetuses influenced gene expression of fetal brain. Extensive exon-level expression changes in the developing brains was observed. Pathway enrichment analysis showed that the ionotropic glutamate receptor pathway and p53 pathway were enriched in female brain only whereas receptor mediated signaling pathways were enriched in the male brain alone. Genes that are known markers of neurons and astrocytes were differentially regulated in male and female brain during development. The study further suggests that regulation of ion transportation via placental matrotrophy may play a role in fetal brain development. Total 18 fetal brain samples (3 gestation days x 2 sexes x 3 biological replicates) were used for RNA sequencing. The three gestation times are days 45, 60 and 90. Total RNA of each sample was used to prepared Illumina sequencing libraries were prepared from the was performed by the Novogen Cooperation Inc. (8801 Folsom Blvd #290, Sacramento, CA 95826). Each library was sequenced to depth of 20 million paired end reads of 150 bases using NovaSeq 6000.