Department of Embryology, Camel Advanced Reproductive Technologies Centre, Government of Dubai, Dubai, United Arab Emirates.
Mol Biotechnol. 2020 Sep;62(9):433-442. doi: 10.1007/s12033-020-00262-y. Epub 2020 Jul 14.
Despite practical implication of cloning in camelids, its broad application has been hampered by technical and biological problems. Method of somatic cell nuclear transfer (SCNT) and oocyte competence are the principal technical and biological factors, respectively, that determine the cloning efficiency. This study, therefore, investigated differential contributions of two SCNT methods [modified handmade cloning (mHMC) vs. conventional (cNT)] and two recipient oocyte sources [abattoir-derived (Vitro) vs. FSH-stimulated (Vivo)] on the efficiency of dromedary camel cloning. The mHMC method supported similar rates of fusion, cleavage, and total blastocyst development, compared to conventional NT (cNT) (94, 89.1, and 68.5% vs. 78.9, 92, and 73.5%, respectively) when Vivo oocytes are used. However, using Vitro oocytes, mHMC supported significantly higher rates for these criteria, except for the cleavage, compared to cNT (95.5, 76.2, 25.2% vs. 75.3, 76.7, and 13.9%, respectively). A total of seven clones were born from mHMC/Vitro (four calves), mHMC/Vivo (one calf), cNT/Vitro (one calf), and mHMC/Vivo&Vivo (one calf)-derived embryos with overall efficiencies of 31.9, 26.6, 20, and 30% for initial pregnancy, 10.6, 6.6, 7.5, and 5% for development to term, and 8.5, 6.6, 2.5, 5% for development to weaving, respectively. To conclude, the quality of recipient oocyte greatly impacts cloning efficiency in vitro with no apparent carrying over effect on cloning efficiency in vivo, but the efficiency of SCNT method may compensate for the initial poor oocyte competence during in vitro and in vivo development of cloned embryos. The introduced mHMC could be a superior alternative to conventional method for simple, fast, and efficient production of cloned offspring in camelids.
尽管在骆驼科动物中克隆具有实际意义，但由于技术和生物学问题，其广泛应用受到了阻碍。体细胞核转移（SCNT）方法和卵母细胞的能力分别是决定克隆效率的主要技术和生物学因素。因此，本研究调查了两种 SCNT 方法（改良手工克隆（mHMC）与传统（cNT））和两种受体卵母细胞来源（屠宰场来源（Vitro）与 FSH 刺激（Vivo））对单峰驼克隆效率的不同贡献。当使用 Vivo 卵母细胞时，mHMC 方法支持与传统 NT（cNT）相似的融合、分裂和总囊胚发育率，分别为 94%、89.1%和 68.5%，而 cNT 分别为 78.9%、92%和 73.5%。然而，当使用 Vitro 卵母细胞时，mHMC 方法除了分裂率外，对于这些标准的支持率明显高于 cNT（95.5%、76.2%、25.2%与 75.3%、76.7%和 13.9%）。总共从 mHMC/Vitro（四只小牛）、mHMC/Vivo（一只小牛）、cNT/Vitro（一只小牛）和 mHMC/Vivo&Vivo（一只小牛）衍生的胚胎中诞生了 7 只克隆，其初始妊娠的总效率分别为 31.9%、26.6%、20%和 30%，发展到足月的效率分别为 10.6%、6.6%、7.5%和 5%，发展到编织的效率分别为 8.5%、6.6%、2.5%和 5%。总之，受体卵母细胞的质量对体外克隆效率有很大影响，对体内克隆效率没有明显的延续效应，但 SCNT 方法的效率可能会弥补体外和体内克隆胚胎发育过程中卵母细胞初始能力差的问题。引入的 mHMC 可能是传统方法的一种替代方法，用于简单、快速、高效地生产骆驼科动物的克隆后代。
