Success of Genetic Engineering

The success of genetic engineering depends upon the consumer acceptance of the materials produced by this new technique. Some products, such as human insulin and oral vaccines, are likely to be accepted as they are expected to be cheaper. Non-food transgenic crops, such as insect and her­bicide resistant cotton, may not evoke public con­cern. However, the edible transgenic crops and animals may generate many controvercies about their safety as food because of their unusual con­tents.

Potential Applications of Clones Of Transgenic Animal

1. Cows, sheep and goats can produce sub­stances having pharmaceutical importance, such as lactoferrin, clotting factor, clot-dissolving protein respectively on a large scale.

2. Pigs can provide parts (pancreas, heart) for transplantation in humans.. Pig's organs are nearly of the same size as those of humans. Transplanta­tion of an organ from one species to another is called xenotransplantation (G. xenos = stranger).

3. Mice are useful for the study of cloning technique.

4. Human cell lines formed by cloning may be used in treating diseases and in replacing parts.

Problems Associated with Genetic Engineer­ing.

No doubt, genetic engineering holds a great promise for correcting genetic defects or for adding genes to improve the species, there are problems associated with the process. If a crop plant carrying gene for resistance to herbicides, natural diseases, and/or insect pests exchanges genes with wild rela­tives via pollen, the offspring could become "superweeds" that would be very difficult to con­trol. Production of a complete map of human genome may raise some ethical questions. Who should have the right to examine someone else's genes ? How should that information be used ? Should a person's genome be a factor in suitability for a job ?

Genetic engineering can be used to transform normally harmless intestinal bacteria into cancer-causing forms, ushering in a new era of biological warfare. These pathogens may escape and cause havoc. Experiments may by chance produce super-viruses to which we might have no defense. An­tibiotics may become ineffective if the bacteria acquire resistance due to the uncontrolled use of recombinant DNAs. Drug-resistant pathogens may be got produced and released into enemy country. For these reasons, some scientists have called for a voluntary end to such a research. Other scientists hold that such a suggestion interferes with scientific freedom. The issue is ethical and not easy to solve.

Cloning of cells, genes and organisms

A population of identical molecules (genes), cells or organisms all derived from the same parent by asexual source is known as a clone (Greek klon = slip, cutting used for propagation). The process of producing genetically similar molecules, cells, or organisms from a common precursor by asexual reproduction in vitro or in vivo is termed cloning.

Examples of Cloning. There are numerous examples of cloning.

Natural Cases. In nature, cloning occurs in bacteria, such as E. coli, and in protists, such as Amoeba proteus, which multiply by an asexual method of binary fission.

Artificial Cases. The famous sheep "Dolly" is a clone of its mother. It was produced nonsexually by inserting the nucleus of a somatic (udder) cell into the enucleated unfertilized egg. Dolly has no father as no sperm par­ticipated in her birth.

Genetically-engineered, economically-im­portant plants are rapidly multiplied by cloning. Actively dividing meristematic cells are taken from the shoot tip and placed in a nutrient medium. Cells are separated. The cells divide mitotically and dif­ferentiate into plantlets. Formation of a carrot plant from the phloem cells of another carrot plant is also cloning.

Totipotency. Cloning results from a unique capacity of cell, namely, totipotency. Cellular totipotency is the ability of a nucleated plant/animal cell to repeatedly divide and differentiate into а complete new plant/ animal in a suitable nutrient medium. In plants, nearly all the cells are totipotent. In animals, only the zygote and stem cells from early embryos are totipotent.