As illustrated below, basic research regarding the biological mechanisms of SCNT has led to scientific advances in the areas of reprogramming, cell fate determination, and epigenetic regulation during development.Moreover, as discussed in the following sections, SCNT in domestic animals will continue to provide promising scientific and practical insights through its application to transgenic and biomedical models.Although the fact that an adult nucleus could indeed direct normal development (resulting in a live offspring) was revolutionary for developmental biology, it followed a series of discoveries that suggested such a possibility (Fig. The initial attempts to artificially clone domestic animals involved embryo splitting.Tags: Essay My Favourite BasketballHow To Problem Solve EffectivelyHow To Write A Service ProposalThesis Theme Add A Second Navigation MenuPhp Variable AssignmentGrading Rubric For Research PaperCite A Song In An EssayRutgers Admission Essay DiversityBibliography Of ThesisParagraph 1 In An Essay
This reconstructed oocyte is activated to continue embryonic development.
Embryos resulting from this procedure can result in the production of a live, genetically identical individual after transfer into a recipient, although at a relative low efficiency (Table 1).
How much have we diverged from nature’s method of cloning?
Even omitting most other forms of plant and animal life and focusing on vertebrates—animals with backbones—examples of clones abound in nature.
At later stages, the blastomeres could no longer independently form a viable blastocyst due to the loss of mass as each blastomere underwent cleavage division.
That did not mean that the blastomere nucleus was incapable of directing full development, but rather that it was unable to stop the developmental clock and replace the lost mass before continuing.Identical twins are the obvious examples, but perhaps more intriguing are armadillos, in which the offspring in a litter are all clones derived from one zygote (9).The simplest form of artificial cloning is embryo splitting—separating the blastomeres of an early embryo and forming two or more smaller embryos.Moreover, clones can be produced using donor cells from sterile animals, such as steers and geldings, and, unlike their genetic source, these clones are fertile.In reality, due to low efficiencies and the high costs of cloning domestic species, only a limited number of identical individuals are generally produced, and these clones are primarily used as breed stock.The word clone can mean different things to different people.In molecular biology, it refers to the process of making identical copies of DNA.Domestic animals can be cloned using techniques such as embryo splitting and nuclear transfer to produce genetically identical individuals.Although embryo splitting is limited to the production of only a few identical individuals, nuclear transfer of donor nuclei into recipient oocytes, whose own nuclear DNA has been removed, can result in large numbers of identical individuals.Subsequently, controversial studies in the 1970s suggested that nuclei from cells that had undergone the first lineage differentiation (that is, cells that had formed the inner cell mass) could direct normal development if substituted for the zygotic nucleus (15).However, failure of other research groups to replicate these studies led some scientist to state that mammalian nuclei after embryonic gene activation were unable to direct development due to irreversible programming changes (16).