International Journal of Aquaculture, 2025, Vol.15, No.2, 45-56 http://www.aquapublisher.com/index.php/ija 53 functional verification of GIHgenes, and the results of using RNA interference and gene editing methods support their inhibitory effects on yolk protein synthesis (Kluebsoongnoen et al., 2020). If the GIH gene can be completely knocked out in vivo and the phenotypes such as early maturity or increased egg laying times of female shrimp will be further proved. Another gene closely related to reproduction is the composition of the vitamin A metabolic pathway. Research has found that retinoic acid signaling plays an important role in the development of crustacean ovary. Some experiments are trying to intervene in retinoic acid synthase or degradation enzyme genes through gene editing to prolong the reproductive activity period of shrimp. 6.3 Research progress on monosexual reproduction and gender control Many breeding species have significant gender 2 phenomenon, that is, there are obvious differences in growth rate and body size of male and female individuals. Some shrimps grow slowly while females grow faster (or vice versa), so obtaining a single-sex population helps to increase yield and neatness. If a single-sex group escapes to the wild and cannot reproduce, it can reduce the risk of ecological invasion. Traditionally, methods to achieve single-sex groups include manual identification sorting and sexual reversal processing, but these methods are time-consuming and labor-intensive or have technical bottlenecks. CRISPR technology provides new ideas for gender control. The gender-determining mechanism of crustaceans is similar to that of insects, and generally secretes IAGfrom male-specific androgen glands to induce male traits. Knocking out the IAGgene of male shrimp by CRISPR can cause female phenotypes to be produced by genetically XY (or ZZ) and achieve sexual reversal. Gui et al.'s research on the spine-tailed white shrimp has confirmed this: the genetic male shrimp not only females in appearance, but also grows ovaries and lays eggs. This means that through gene editing, we can turn male shrimp into functional female shrimp. If these sexual reversal females are mated with normal males, it is possible to give birth to all male offspring (because the reversal females do not have female chromosomes, only male components are provided). The next generation that reproduces in this way will manifest as normal males if they are still XY and have no IAGdefects (Gui et al., 2016). Therefore, a whole male shrimp population can be mass-produced for breeding, thereby increasing yield by taking advantage of the gender-type 2 advantages. Similarly, if the target is a total female population, acquired reversal of male shrimp (genetic female to male). 7 Ethical, Safety and Regulatory Considerations of CRISPR Applications 7.1 Biosafety and ecological risk assessment When applying gene editing technology to farm shrimp, the first thing to consider is biosecurity and ecological impact. Although gene-edited shrimp does not carry exogenous transgenic fragments themselves, their artificially induced genetic variations may give them some significant advantages (such as faster growth or stronger disease resistance), and these characteristics may have an impact on the ecosystem if they spread to nature under uncontrolled conditions. To ensure biosecurity, scientific research and breeding units should establish strict biosecurity systems. During the experimental stage, gene-edited shrimps should be cultivated in a controlled circulating water system, and wastewater can only be discharged after treatment to prevent embryos or individuals from leaking. Transportation and use of gene-edited shrimp seedlings must have a complete traceability and isolation mechanism. In addition to ecology, in terms of food safety, it is necessary to confirm that gene editing will not introduce harmful substances or sensitizing ingredients (Zhao and Wang, 2024). Typical variations produced by CRISPR are base deletions or substitutions, which are essentially no different from natural mutations and generally do not produce completely new proteins. However, it is not ruled out that some edits may alter metabolic pathways, resulting in accumulation of specific substances. Therefore, before the new product is promoted, it should be tested for abnormal components in its muscles, hepatopancreas and other edible tissues according to the food safety assessment process. Bioethical aspects (Parra et al., 2021), involve the public's acceptance of animal genetic modification, such as whether it is considered acceptable to modify organisms for human use. Compared with mammals, the public usually has fewer concerns about modifying invertebrates, but it also needs to introduce the purpose and process of gene editing transparently and openly to avoid causing unnecessary panic.
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