Transcriptomic Comparative Analysis of Two Breeds of Mongolian Sheep at 16-day Embryos

Early embryonic development determines fetal and adult development. However, little is known about the specific development of the early Mongolian sheep embryo. We aim to analyze the differentially expressed genes (DEGs) between 16-day embryos of two breeds of Mongolian sheep, namely, Hulunbuir short-tailed sheep and Ujumqin sheep, by mRNA sequencing. A total of 2152 DEGs were identified. Significantly DEGs include WNT5A, WNT2, AXIN2, BMP5, TGFB2, and SMAD9, which are involved in multiple signaling pathways, and genes involved in digestion and absorption and cellular differentiation, such as DPP4, ACE2, PLPP1, CD22, CD44, TEC, and JAK1. In the pathway analysis, the development of Hulunbuir short-tailed sheep 16-day embryo H(E16) highlighted pathways primarily associated with cellular interactions and organogenesis. These pathways are critical for transcriptional control during early embryonic development, especially organ formation. Genes that sophisticate organs and body mechanisms, and genes associated withrotein and fat digestion, hematopoietic stem cell lineage and osteoblast differentiation, are enriched during the development of the Ujumqin sheep 16-day embryo U(E16). Our work provides important complementary reference data for the study of early embryonic development in sheep.