A team of American scientists has produced the first non-human primate clone. Tetra, a Rhesus monkey baby, was born in September last year at the Oregon Regional Primate Research Center in the US. However, the creation of Tetra was not, done by nuclear transfer as Dolly the sheep was. Instead, embryo splitting was used to create identical embryos, of which Tetra was one. During the research, 107 Rhesus embryos were split in total, and in the case of Tetra, an eight-cell embryo from which the shell had been removed, was 'mechanically disrupted' to form four individual two-cell embryos. Two of these embryos were implanted into each of two surrogate mothers - one of whom miscarried. The second monkey had an uneventful pregnancy and became Tetra's 'mother'.
The implications of this mode of 'cloning' are great for medical research. Gerald Schatten, leader of the Oregon team has pointed out that a group of sheep clones created by nuclear transfer all differ in size and temperament. There have also been concerns about the affect mitochondria from enucleated eggs may have on nuclear transfer clones. Embryo splitting produces genetically identical offspring - valuable to medical research as it may reduce the number needed for some experiments and create new opportunities to study disease and new treatments.
The aim of the research and development of these 'true clones' is to produce models for testing whether it is possible to grow stem cells for transplant into patients with failing organs. Most new medical techniques are tested on mice. Monkeys, being genetically more similar to humans, may provide more reliable results. However, the research has inevitably re-sparked the debate over the possibilities and implications of human cloning and the ethics of human stem cell research.