New Developments or Research in Genetic Cloning: Summary


Since genetic cloning is a very wide topic, the focus of my paper lies
mainly on the new discoveries which might be beneficial to human beings. The
focus of the first section of the paper is on the various cloning techniques
geneticists use nowadays. They techniques included range from the simplest and
suitable for all situations, to complicated and suitable for certain areas.

The second section of the paper, the longest section, discusses five of
the many researches performed over the last five years. The researches are
arranged in descending chronological order, dating from February 1997, to April
1992. These researches are discussed because they all have one thing in common:
they may be beneficial to human beings later on. For example, the newest entry
in my paper, and perhaps the one that shocked the whole world, was the report
about the first successful clone mammal from non-embryonic cells. This will be
helpful in the future for patients waiting for organ transplants. Scientists
will be able to clone a fully functional organ, and replace it with the damaged
one. The report on the cloning of the human\'s morphine receptor is advantageous
to us because this helps scientists to develop new analgesics.

The third section of the paper contains a brief discussion about the
advantages and the disadvantages of genetic cloning. It speculates how our
future will improve due to the technologies we are developing, and also the
biggest drawbacks which might come from it.

The last part of the paper, is the explanation of complicated terms used
in this paper. The terms which will be explained are printed in bold terms
throughout the paper. This section, the glossary, is like the ones which
appears in textbooks.

New Developments or Research in Genetic Cloning


Genetic cloning is one of the many aspects which has been recently
introduced to improve our quality of live. Researchers are trying to improve
our lives everyday applying genetic engineering onto our everyday lives. Cows
can be genetically altered to produce more milk, receptors in our body could be
cloned to improve our health. The techniques and new research reported in this
paper is just one tree out of the whole forest of genetic engineering.

Part I: Techniques of Genetic Cloning

Geneticists use different cloning methods for different purposes. The
method used to identify human diseases are different than the method used to
clone a sheep. The following are used techniques in genetic cloning.

Recombinant DNA

In recombinant DNA, the desired segment is clipped from the surrounding
DNA and copied millions of times. Each restriction enzyme recognizes a unique
nucleotide sequence wherever it occurs along the DNA spiral. This nucleotide
sequence, known as the recognition site is a short, symmetric sequence of bases
repeated on both strands of the double helix. After the segment is removed, the
ragged, or "sticky" ends that remain after cleavage by the restriction enzyme
allow a DNA restriction fragment from one organism to join to the complementary
ends. This method allows a foreign DNA to be cloned in a bacteria. The result
will be identical clones of the original recombinant molecule in hundreds of
copies per cell.

Polymerase Chain Reaction (PCR)

The PCR is a method of gene amplification. It is a better method than
bacterial cloning because of its greater sensitivity, selectivity, and speed.
Moreover, it does not require bacterial vectors and rapidly amplifies the chosen
segment of DNA in the test tube without the need for living cells.

In this process, the DNA sequence to be amplified is selected by primers,
which are short pieces of nucleic acid that correspond to sequences flanking the
DNA to be amplified. After an excess of primers is added to the DNA, together
with a heat-stable DNA polymerase, the strands of both the genomic DNA and the
primers are separated by heating and allowed to cool. A heat-stable polymerase
lengthens the primers on either strand, therefore generating two new, identical
double-stranded DNA molecules and doubling the number of DNA fragments.

Positional Cloning

This method is used when scientists need to identify human disease genes.
The overall strategy is to map the location of a human disease gene by linkage
analysis and to then use the mapped location on the chromosome to copy the gene.
There are two essential requirements for mapping disease genes. Firstly, there
must be sufficient numbers of families to establish linkage and, second,
adequate informative DNA markers. Once suitable families are identified, the
investigators determine if diseased people in the family have particular DNA
sequences at specific locations that healthy family members do not. A
particular DNA marker