Nuclear transfer in human medicine and animal breeding

Cloning has a number of potential applications in human medicine and animal breeding, but the efficiency of production of developmentally competent em bryos and healthy animal offspring needs to be improved. The primary defici ency appears to be incomplete or abnormal nuclear reprogramming after nucle ar transfer, and it is hypothesized that epigenetic regulators of transcrip tion cannot always be converted to the embryonic pattern and this leads to implantation failure, gestational abnormalities and poor health of offsprin g. Research needs to be focused on this aspect of development for nuclear t ransfer embryos. However, there is a gradual demand for commercial applicat ion for cloning in animal production, transgenesis and animal biopharmaceut icals, particularly in milk. These applications will expand in the near fut ure. There is little application of nuclear transfer in human medicine at p resent, but important applications may be demonstrated for prevention of th e inheritance of mitochondrial mutations, prevention of age-related aneuplo idis in women, artificial gametes for sterile individuals or couples and fo r therapeutic cloning to enable cell and gene therapies.