Transcriptome Data Reveals Hypoxic Adaptability on Embryonic Cardiac Development in Tibetan Chickens

The Tibetan chicken (TC) is a small indigenous breed native to the Qinghai–Tibet Plateau in China, exhibiting remarkable adaptation to the plateau’s extreme high-altitude environment. Its strong hypoxia tolerance is reflected in the ability to maintain normal embryonic cardiac structure and function during hypoxic incubation or high-altitude incubation. This study performed transcriptome sequencing of embryonic heart tissues from TC and White Leghorn (WL) incubated for 9, 11, and 16 days in Lhasa (altitude of 3650 m). A total of 1788 differentially expressed genes (DEGs) were identified through inter-breed comparison. Some DEGs were enriched in signaling pathways related to angiogenesis, apelin signaling, and myocardial contraction. Through integrating temporal expression analysis and weighted gene co-expression network analysis (WGCNA), we identified six key candidate DEGs (CREB3L2, MYH7B, CREB1, LOXL2, MICAL2, and AKAP13) that are involved in hypoxic response, myocardial structural remodeling, and regulation of signaling pathways. These genes likely represent core components of the molecular network underlying hypoxic adaptation in TC embryos. Overall, our findings provide a molecular basis for understanding the genetic mechanisms of hypoxic adaptation during embryonic cardiac development in chickens.