HUMAN CLONING TECHNIQUES

Human Cloning Techniques

The procedures used in cloning human embryos are very similar to the cloning of animal embryos, except for the zona pellucida. Several sperm cells and mature egg cells are gathered from donors at fertility clinics, and are combined in a petri dish using in vitro fertilization procedures to form an embryo. In an alternate process, already produced embryos are gathered from fertility clinics that have embryos left over from prior in vitro clients. The acquired embryo is placed in a petri dish and is allowed to develop into a mass of two to eight cells. Next, a chemical solution is added that dissolves the zona pellucida that covers the embryo. The zona pellucida is a protective protein and polysaccharide membrane that covers the internal contents of the embryo, and provides the necessary nutrients for the first several cell divisions that occur within the embryo. After the zona pellucida is dissolved the cells within the embryo are freed. These two to eight cells are then collected by the researchers and placed in separate petri dishes.

These embryonic cells are called blastomeres, or cells that are a part of the hollow ball of cells know as the blastula. The embryonic cells are then each coated with an artificially produced zona pellucida. The individual cells then are considered new embryos, all of which share the same exact genetic information. In effect at this point the science has produced multiple copies of life that could have never before existed. Do we as a society have the moral wisdom to determine the direction or understand the implications that this science provides our species? These cells will divide and will eventually form a human being, if allows to develop. Hall and Stillman's attempt to produce human embryo clones was only somewhat successful. The embryos that they used in their experiments were not able to produce human beings, because they were double fertilized, that is fertilized by more than one sperm cell. These embryos will eventually die during sometime in their development because of the extra set of chromosomes donated by the second sperm cell. The researchers removed two or more embryonic cells from seventeen different abnormal embryos, and allowed these cells (blastomeres) to develop into new individual embryos, using the above stated steps. These new embryos grew and divided at the anticipated rate, however, all eventually died before reaching the 64 cell stage.

As was stated before, from two to eight embryonic cells may be removed from the original embryo, depending on the development of the embryo, but the experiments completed by Hall and Stillman showed that the best results were obtained from embryos that had divided only twice. These new embryos reached the 32 cell stage, whereas other original embryos of four or more cells, barely made it to the 16 cell stage. It is not known whether these new cloned embryos would have developed further if they had not been abnormal. Hall believes that the embryos might have developed even further in the more natural environment of the uterus.