Advances in the Molecular Regulatory Mechanisms of Testicular Development and Spermatogenesis in Yaks
TL;DR
This review summarizes molecular regulatory dynamics throughout the full-life-cycle development of yak testes, highlighting core molecular networks governing spermatogonial stem-cell self-renewal, meiotic initiation, and sperm morphogenesis and further integrates the modulatory roles of the testicular microenvironment and epigenetic modifiers into a unified conceptual framework.
Abstract
Simple Summary The yak is a species endemic to the Qinghai–Tibetan Plateau and exhibits notable male reproductive traits under hypoxic and low-temperature stress. Specifically, testicular weight is markedly lower than that of cattle. Nevertheless, according to reported data from different experiments, although its single ejaculate volume is lower than that of Tibetan cattle, it can still maintain comparable fresh sperm motility. These features make it an ideal natural model for investigating the interplay between energy metabolism and reproductive adaptation. This review summarizes molecular regulatory dynamics throughout the full-life-cycle development of yak testes, highlighting core molecular networks governing spermatogonial stem-cell self-renewal, meiotic initiation, and sperm morphogenesis. It further integrates the modulatory roles of the testicular microenvironment and epigenetic modifiers into a unified conceptual framework. By taking advantage of male sterility in cattle-yak, essential checkpoints governing spermatogenesis can be inferred from its defective phenotype. Finally, we discuss prospects for leveraging single-cell multi-omics and gene-editing technologies to deepen mechanistic understanding of high-altitude reproductive adaptation. These insights may provide theoretical underpinnings for improving yak fertility and supporting crossbreeding programs.
