基因,蛋白,免疫 课程之蛋白组学 8.pdf

Somatic Cell Nuclear Transfer (Cloning) Efficiency The overall efficiency of cloning is typically between 0 and 3 % (number of live offspring as a percentage of the number of nuclear transfer embryos), irrespective of the species, the donor cell type or technique. However, this is the cumulative result of losses at each stage of the cloning process. The following tables provide a summary of the data for each published report on somatic cell (fetal to adult cells) nuclear transfer to date. Where the appropriate data was made available, the table provides cloning efficiency for each major stage of the process: % Embryos formed from NT Oocytes: % of morula and/or blastocysts formed from the number of NT (nuclear transfer) oocytes created. The number of NT oocytes is the number of oocytes that were enucleated and injected or fused with donor nuclei. In some reports, only the number of oocytes cultured, or surviving activation or injection is given and the figures are denoted by * with a corresponding footnote. No. Implantation Sites: This column refers to mice only, and shows how many fetuses implanted into the uterus but were subsequently reabsorbed. No. Pregnant (no. of recipients): This column is provided for each livestock species. The time of pr egnancy confirmation is species dependent. (no. of recipients) refers to the total number of recipients to which embryos were transferred. No. Pregnancies Lost: Refers to the number of recipients that had lost their fetuses at various stages throughout gestation. Live Offspring (% embryos transferred): Refers to the number of live offspring born and is also given as a % of the total number of embryos transferred (normally morula or blastocyts, however some studies transfer 2,4,and 8 cell). No. Survived: Refers to the number of live offspring that survived. CE: Cloning Efficiency is the number of live offspring expres