摘要
2.2.3 基因(基因组)编辑生产基因敲除或敲入的转基因动物.最初用于生产转基因家畜的方法会导致随机转基因的插入,因此需要新技术来提高基因靶向效率。通过原核注射将DNA递送到受精卵中的方法在概念上是简单的,但该方法在技术上具有挑战性,并且注射的DNA构建体会随机整合到基因组中,产生不可预测的转基因表达谱。此外,显微注射会损伤受精卵,并且还需要昂贵的设备。
As the world’s population and living standards increase, demands for high quality pork pro-tein increase substantially in the face of reducing resources. This requires not only improved diets,but also biotechnology-based breeding to generate swine with desired production traits. Biotechnologycan be classified as the cloning of animals with identical genetic composition(via somatic cell nucleartransfer, embryonic cell nuclear transfer, or embryo spitting) or genetic engineering(via recombinantDNA technology and gene editing) to produce transgenic animals or microorganisms. Cloning helps toconserve species and breeds, particularly thosewith excellent biologic and economic traits. Recombinant DNA technology combines genetic ma-terials from multiple sources into single cells togenerate proteins, and is the basis for gene(genome) editing. The latter involves the deletion, insertion or silencing of genes to produce: transgenicpigs with important production traits; or microorganisms without an ability to resist antimicrobial sub-stances. Current gene-editing tools include the use of zinc finger nuclease(ZFN), transcription activa-tor-like effector nuclease(TALEN), or clustered regularly interspaced short palindromic repeats-associ-ated nuclease-9(CRISPR/Cas9) as editors. ZFN, TALEN, or CRISPR/Cas9 components are deliveredinto target cells through transfection(lipid-based agents, electroporation, nucleofection, or microinjec-tion) or bacteriophages, depending on cell type and plasmid. Compared to the ZFN and TALEN edi-tors. CRISPR/Cas9 offers a higher efficiency, greater ease of designing, and greater flexibility in genet-ic engineering. To date, transgenic pigs have been generated to express bovine growth hormone, bacte-rial phytase, fungal carbohydrases, plant and C. elagan fatty acid desaturases, and uncoupling protein-1; and lack myostatin, α-1,3-galactosyltransferase, or CD163[a cellular receptor for the porcine repro-ductive and respiratory syndrome virus ("blue ear disease")]. Biotechnology holds promise in improvingthe efficiency of swine production and developing alternatives to antibiotics in the future.
出处
《饲料工业》
北大核心
2019年第6期58-64,共7页
Feed Industry
