RESUMEN
Zinc finger protein X-linked (Zfx) was regarded to be a sex determination factor and plays a critical role in spermatogenesis. RNAi is an effective method of silencing Zfx mRNA expression. However, there has been little research on the use of RNAi technology to control the sex of the offspring of red deer (Cervus elaphus). The objective of this study was first to explore an efficient method to alter the red deer offspring sex-ratio by silencing the gene Zfx during spermatogenesis. Three recombinant expression vectors pLL3.7/A, pLL3.7/B, and pLL3.7/C were constructed to interrupt the Zfx gene. The results showed that the expression of Zfx mRNA was significantly silenced by pLL3.7/A (P < 0.01), compared with the control group. The group injected with pLL3.7/A produced 94 red deer, including 68 males and 26 females. The male rates (72.34%) were significantly higher than the control groups (P < 0.01). Our result suggests that Zfx siRNA is a useful approach to control offspring sex in red deer. This study further confirms that the Zfx gene plays a significant role in the process of X spermatogenesis.