# Theoretical discussion on gene editing and cross-species characteristics Gene editing technologies (such as CRISPR-Cas9) do provide humans with powerful tools for editing the genome, but integrating the characteristics of other species into the human genome faces extremely complex scientific and ethical challenges.： ## Scientific difficulties 1. **System complexity**: The underwater breathing of fish is not controlled by a single gene, but a complex gene network involving gill structure, gas exchange system, and related metabolic networks. 2. **Anatomical differences**: Humans and fish have fundamental anatomical differences. We lack the vascular structure and neural control system that support gill function. 3. **Developmental path differences**: These characteristics have been determined early in embryonic development, and simply adding adult genes may not activate the complete developmental path. ## Current practical application Instead of pursuing cross-species identity transplantation, scientists are more focused on： -Treatment of genetic diseases (such as sickle cell anemia, cystic fibrosis) -Enhance existing human abilities (such as genetic research related to muscle development) -Fight common diseases (such as genes related to heart disease risk) ## Ethical considerations Such research involves major ethical issues, including： -Safety of human experiments -Unknown long-term consequences - Does it represent improper intervention in human nature? - Fair access issues and social impact At present, the scientific community and ethical institutions generally believe that gene editing of human embryos should be limited to the treatment of serious diseases, rather than enhancing characteristics or adding non-human characteristics.