GENETIC ENGINEERING
WHAT IS GENETIC ENGINEERING
― Also known as genetic modification, is the direct manipulation of the genes in an
organism.
― To obtain a desired characteristic, the relevant gene from a cell in one organism is
transferred to a cell in another organism.
― The organism receiving the gene is thus genetically modified and is known as a
transgenic organism.
Genetically modified – GM
Genetically modified organism - GMO
― Genetic engineering also
replaces faulty / missing genes that cause disorders / diseases.
― This ensures that the correct protein is synthesised.
― The basis of the process includes the following steps;
o The relevant gene is identified in a healthy cell, extracted, and cut from
the DNA.
o The isolated gene is inserted into the defective cell by means of vectors
[viruses / bacteria].
A vector is an organism that transfers something. In this case an isolated gene is
transferred by the vector to the defective cell.
o It becomes integrated in the organism’s genome.
o The correct protein is synthesised, and the desired trait is expressed in the
phenotype.
― Genetic engineering results in the formation of a new DNA sequence in the
recipient cell. The new DNA formed is known as recombinant DNA.
The word “recombinant” refers to the new combination of DNA in the organism that
received the new gene.
― The organism that possesses the recombinant DNA is the transgenic organism
that can now synthesise the protein coded by the new gene[s].
The integration of genes [for therapeutic purposes] in cells w. faulty / missing genes is
known as gene therapy.
GENETICALLY MODIFIED ORGANISMS [GMOS]
― Genetically modified organisms are the result of genetic engineering.
― GMOs are utilised in a variety of human activities to improve quality of life /
productivity.
― GMOs maybe microbes / plants / animals.
IMPORTANCE OF GENETIC ENGINEERING AND GMOS
― Genetic engineering affects many aspects of our lives and our enviro.
― It plays a role in;
o Synthesis of medicinal drugs.
o Cloning.
, o Production of new crops.
o Stem cell research.
IN MEDICINE
― Two aspects of the importance of genetic engineering in medicine are discussed:
o The production of artificial hormones e.g. insulin.
o The production of vaccines.
Production of insulin
Diabetes mellitus is a disease where the pancreas does not produce enough insulin.
The hormone insulin controls the glucose concentration in the blood. Type-I diabetes
can be treated successfully by daily insulin injections / by a nasal spray application.
Previously, insulin was extracted in small quantities, and at great cost, from the
pancreas of freshly slaughtered cattle and pigs. Animal insulin is not exactly the same
as human insulin and does not control blood sugar levels as effectively.
― Human insulin can be produced synthetically through genetic engineering by
using recombinant DNA technology.
― Insulin is produced as follows;
o The DNA w. the gene coding for the production of insulin is removed from
healthy human pancreatic cells.
o Enzymes known as restriction enzymes are used to cut DNA into segments
to isolate the specific gene.
o Escherichia coli [E. coli], a bacterium present in the human intestine, is
used to produce insulin.
Some bacterial genes are found on ring-shaped DNA molecules called plasmids.
Plasmids are not part of the chromosomes of a bacterium cell and replicate
independently.
o Plasmids are removed from the E. coli bacteria.
o Restriction enzymes are used to cut the plasmids.
o The human gene, coding for the production of insulin, is inserted into the
opened bacterial plasmid aided by the enzyme DNA ligase.
o The plasmid joins ends to form the ring shape again and the human gene
is now a part of the new recombinant DNA.
o The recombinant DNA [the plasmid] is placed
back into the host cell, E. coli.
o E. coli accepts the new gene as part of its
genetic material and produces insulin.
o The bacteria are placed in a special
fermentation tank where they reproduce
rapidly. Replication of the desired gene takes
place as soon as E. coli reproduces. Large
numbers of bacterial cells w. the desired gene
coding for insulin production are formed. The
insulin is extracted from the bacteria, purified
and used o treat diabetes.
― The demand for insulin increases annually. In 1990
there were approx. 30 million diabetics worldwide, but
the figure has risen to 300 million within 20 years.
WHAT IS GENETIC ENGINEERING
― Also known as genetic modification, is the direct manipulation of the genes in an
organism.
― To obtain a desired characteristic, the relevant gene from a cell in one organism is
transferred to a cell in another organism.
― The organism receiving the gene is thus genetically modified and is known as a
transgenic organism.
Genetically modified – GM
Genetically modified organism - GMO
― Genetic engineering also
replaces faulty / missing genes that cause disorders / diseases.
― This ensures that the correct protein is synthesised.
― The basis of the process includes the following steps;
o The relevant gene is identified in a healthy cell, extracted, and cut from
the DNA.
o The isolated gene is inserted into the defective cell by means of vectors
[viruses / bacteria].
A vector is an organism that transfers something. In this case an isolated gene is
transferred by the vector to the defective cell.
o It becomes integrated in the organism’s genome.
o The correct protein is synthesised, and the desired trait is expressed in the
phenotype.
― Genetic engineering results in the formation of a new DNA sequence in the
recipient cell. The new DNA formed is known as recombinant DNA.
The word “recombinant” refers to the new combination of DNA in the organism that
received the new gene.
― The organism that possesses the recombinant DNA is the transgenic organism
that can now synthesise the protein coded by the new gene[s].
The integration of genes [for therapeutic purposes] in cells w. faulty / missing genes is
known as gene therapy.
GENETICALLY MODIFIED ORGANISMS [GMOS]
― Genetically modified organisms are the result of genetic engineering.
― GMOs are utilised in a variety of human activities to improve quality of life /
productivity.
― GMOs maybe microbes / plants / animals.
IMPORTANCE OF GENETIC ENGINEERING AND GMOS
― Genetic engineering affects many aspects of our lives and our enviro.
― It plays a role in;
o Synthesis of medicinal drugs.
o Cloning.
, o Production of new crops.
o Stem cell research.
IN MEDICINE
― Two aspects of the importance of genetic engineering in medicine are discussed:
o The production of artificial hormones e.g. insulin.
o The production of vaccines.
Production of insulin
Diabetes mellitus is a disease where the pancreas does not produce enough insulin.
The hormone insulin controls the glucose concentration in the blood. Type-I diabetes
can be treated successfully by daily insulin injections / by a nasal spray application.
Previously, insulin was extracted in small quantities, and at great cost, from the
pancreas of freshly slaughtered cattle and pigs. Animal insulin is not exactly the same
as human insulin and does not control blood sugar levels as effectively.
― Human insulin can be produced synthetically through genetic engineering by
using recombinant DNA technology.
― Insulin is produced as follows;
o The DNA w. the gene coding for the production of insulin is removed from
healthy human pancreatic cells.
o Enzymes known as restriction enzymes are used to cut DNA into segments
to isolate the specific gene.
o Escherichia coli [E. coli], a bacterium present in the human intestine, is
used to produce insulin.
Some bacterial genes are found on ring-shaped DNA molecules called plasmids.
Plasmids are not part of the chromosomes of a bacterium cell and replicate
independently.
o Plasmids are removed from the E. coli bacteria.
o Restriction enzymes are used to cut the plasmids.
o The human gene, coding for the production of insulin, is inserted into the
opened bacterial plasmid aided by the enzyme DNA ligase.
o The plasmid joins ends to form the ring shape again and the human gene
is now a part of the new recombinant DNA.
o The recombinant DNA [the plasmid] is placed
back into the host cell, E. coli.
o E. coli accepts the new gene as part of its
genetic material and produces insulin.
o The bacteria are placed in a special
fermentation tank where they reproduce
rapidly. Replication of the desired gene takes
place as soon as E. coli reproduces. Large
numbers of bacterial cells w. the desired gene
coding for insulin production are formed. The
insulin is extracted from the bacteria, purified
and used o treat diabetes.
― The demand for insulin increases annually. In 1990
there were approx. 30 million diabetics worldwide, but
the figure has risen to 300 million within 20 years.
