Identification of candidate genes for hypoxic adaptation through transcriptomic data of embryo hearts in Xueyu White Chickens

The Xueyu White Chicken (XYW) is a breed bred in the Qinghai-Tibet Plateau from a hybrid of the Tibetan Chicken (TC) and White Leghorn (WL). The breed has good laying performance and high adaptation to hypoxic environments. The hatchability of XYW on the Qinghai-Tibet Plateau is higher than that of WL. In this study, the transcriptome data of embryonic hearts were obtained from XYW and WL on days 9, 11, and 16 of incubation, and 561 differentially expressed genes (DEGs) were screened by comparing the two breeds. Several DEGs (NOS1, AKT3, ERBB4, TBX2O, etc.) were enriched in categories such as response to hypoxia, angiogenesis, heart development, and cardiac muscle contraction. Through ClusterGVis analysis, the DEGs were divided into different groups, and most genes had greater differences in expression levels in the early stages of development, and the differences gradually decreased as the embryo developed. In addition, the targeting relationships between key transcription factors (TFs) (HAND, TBX20, KLF7, and CREB1) and DEGs (FABP1, NOS1, AKT3, GNB3, etc.) were constructed to investigate their molecular mechanisms. This study provides a basis for the genetic analysis of hypoxic adaptation in chicken embryos.