Genetic engineering involves manipulating genes through techniques like recombinant DNA and gene splicing. The first recombinant DNA was created in 1972 by Paul Berg. Genetic engineering is used to produce insulin through biopharming. DNA cloning makes copies of genes through cell-based or cell-free methods involving vectors, host cells, and selection/expression of genes. Genetic diagnosis analyzes DNA directly through tests like mutation analysis or indirectly using genetic markers for linkage analysis to identify unknown defective genes. Applications of genetic engineering include medicine through techniques like in vitro fertilization, gene therapy, agriculture through genetically modified crops and animals, and improving food quality and environmental sustainability. Risks include health issues from allergens/toxins and environmental impacts of transgenic organisms

1. Ma. Lunie Fe Bianca M. Otacan
BMLS-1C
MTSTS
10-02-14
Chapter 7
Genetic engineering
7.1: Genetic Engineering: An overview
Genetic engineering involves methods, techniques, and procedures used in gene
manipulation. The oldest of these is the recombinant DNA (rDNA) technique, or gene splicing.
The first recombinant DNA was created by molecular biologist Paul Berg in 1972 from the
cancer-causing monkry virus SV-40 and the virus lambda. This marked the birth of the field of
genetic engineering. The method of producing insulin using genetic engineering was discovered
in 1979. This is the transgenic drug in biopharming.
7.2: DNA Cloning
The process of creating copies, or clone, of a single gene or DNA segment is known as
DNA Cloning. DNA cloning can be cell-based or cell-free (using the polymerase chain
reaction). Cell-based cloning is carried out as follows:
1. Obtaining DNA Fragments-isolation of the desired DNA can be done by restriction-
endonuclease digestion, etc.
2. Joining the vector-the isolated DNA fragments can be transferred into a living cell
through the use of a cloning vehicle known as a “vector”.
3. Introduction to host cell-“trasnformation” because of the host may be altered due to the
fusion of the foreign DNA with the native DNA.
4. Selection-involves determining which host cells have successfully replicated the desired
genes.
5. Expression-involves the genetic expression of the received DNA.
7.3: Genetic Diagnosis and Screening
The two ways by which DNA can be analyzed are by
 direct test (that is, direct examination of the genes)
 fast and sensitive but it can only be used if the defective gene is known.
 An example of a direct DNA test is the mutation analysis for cystic
fibrosis.
 indirect test (that is, use of markers or linkage analysis)
 it is used if the type of gene mutation that causes the disease is not yet
identified.

2. Ma. Lunie Fe Bianca M. Otacan
BMLS-1C
MTSTS
10-02-14
 In this case, genetic markers, which are DNA sequences that have been
traced to specific locations on chromosomes, are used.
 Linked markers are a set of markers close to a particular gene.
Diagnostic techniques used in Genetic Diagnosis and Screening Polymerase Chain Reaction
the PCR process:
step 1: Denaturation-breaking double stranded DNA
step 2: Annealing-binding of a primer to a DNA strand
step 3: Extension-elongation od DNA strand
Ligase Chain Reaction
 Ligase Chain Reaction-an alternative procedure to PCR that minimizes impurities
associated with the PCR assay.
 Antisense Technology-inhibits a gene function by complementary base pairing to the
genetic target. Provides the potential for “turning off” selected genes.
 Transgenetic technology-paves the way for introducing foreign genes into experimental
animals to make them transgenic.
Implications of Genetic Testing
 Genetic Discrimination-those who are at risk for certain genetic disorders can be denied
life and/or health insurance.
 Eugenics-negative eugenics is the belief that the human population can be improved by
preventing the reproduction of indiduals with undesirable traits.
 Genetic Determinism-this is the belief that aperson’s behavior, physical characteristics,
and personality are dtermined by his or her genes.
Pre-natal Diagnosis
Prenatal screening involves testing for diseases or conditions of afetus.
7.4: Applications of Genetic Engineering
The tehcnological innovations in genetic engineering offer remarkable solutions to
problems in health, food shortage, and pollution. With the advancements in technology, genetic
engineering has unlimited potential for enhancing the quality of human life.
Applications of Genetic Engineering in Medicine

3. Ma. Lunie Fe Bianca M. Otacan
BMLS-1C
MTSTS
10-02-14
Can be categorized into diagnosis (pre- and postnatal) and treatment. Techniques in
genetic engineering include sperm banking and in vitro fertilization.
In vitro fertilization steps:
 Stimulants-also known as superovulation because multiple eggs are stimulated and
brought to maturation and ovulation.
 Follicular aspiration-involves the retrieval of eggs from the follicles inside the ovary.
 Insemination and fertilization-involves the mixing of the male’s sperm with the
female’s eggs. Fertilization can be done in two ways: allowing the sperm to naturally
enter the egg, or injecting the sperm into the egg in a process known as intracytoplasmic
sperm injection.
 Embryo culture-the fertilized egg divides and becomes an embryo.
 Embryo transfer-the resultant embryo is transferres to the female’s uterus through a thin
tube.
Reasons for performing IVF
Main reason is infertility.
Risks associated with IVF
 Physocological stress and depression
 Bloating
 Abdominal pain
 Moodswings
 Headaches
 Ovarian hyperstimulation syndrome
 Other side effects of fertility drugs
 Higher probability of giving birth to premature babies
 Higher probability of multiple pregnancy
Sperm banking
A facility or place where sperm is stored and kept viable under controlled conditions. The
sperm stored in such a facility can be used for a number of purposes:
 Artificial insemination-involves injection of sperms into the female’s vagina or cervix

4. Ma. Lunie Fe Bianca M. Otacan
BMLS-1C
MTSTS
10-02-14
 Surrogacy arrangments and creating embryos for embryo donation
 Resarch or educational purposes
 Personal purposes-this includes preserving the reproductive capacity in males who
undergo surgery, chemotherapy, and so on.
Sex selection and prediction
The attempt to control the sex of one’s offspring is knwon as sex selection. One of the
reasons for sex selection is “ family balancing”, that is to have equal or an almost equal number
of daughters and sons. The medical benefits of sex selection include the possibility of preventing
the transmission of sex-linked diseases, such as hemophilia and parkinson’s disease.
Sex selection can be carried out at various stages:
 Prefertilization-involves the separation of X chromosome-bearing and Y chromosome-
bearing sperms.
 Postfertilization-PCR is used to determine the sex of the embryo by detecting the
presence of the sex-determining region (srY) in the embryo.
 Postimplantation-techniques to determine sex during the postimplantation stage include
ultrasound, chorionic villus sampling (CVS), and amniocentesis.
Gene Therapy
A technique that involves the replacement of a disease-causing gene with normal
(therapeutic) gene. a carrier molecule known as a vector is needed to deliver the therapeutic
gene. Gene therapy is carried out as follows:
1. Isolation of the gene coding for the desired protein
2. Delivery of the gene into the cell by means of a vector
3. Integration of the gene into the host DNA
4. Synthesis of the protein
5. Delivery of the protein to the target cell to elicit the desired action.
The various types of gene therapy are described as follows:
 Somatic gene therapy
 Germline gene therapy
 Preventive gene therapy

5. Ma. Lunie Fe Bianca M. Otacan
BMLS-1C
MTSTS
10-02-14
Some limitations of gene therapy are as follows:
 The inserted gene may be considered as foreign body of the recipient so it will be
attacked and destroyed by antibodies.
 There is the possibility that the virus that is used as a vector will regain its ability to
induce disease and control gene action.
 Gene therapy works on a single gene, however most diseases are caused by multiple
genes.
 The effect of gene therapy is short-lived because the cell are rapidly dividing.
Applications of genetic engineering in agriculture
Techniques in genetic engineering are used to manipulate the genetic material in plants
and animals. New varieties of plants with improved quality, productivity, and value are created.
Genetic modification in animals involves changing, adding, or removing genes to modify
characteristics, such as to enhance growth and confer resistance to certain diseases.
The following are some of the applications of genetic engineering in the field of agriculture:
 Genetically engineered crops-have desirable traits such as increased productivity and
higher nutritional value.
 Genetically engineered animals-also known as trangenic animals. Desirable traits are
introduced into animals to improve their characteristics.
 Improvement in quality-food processing is improved by increased purity, more reliable
supply, cost reductions and high-yield efficiency.
 Environmental benefits-crops become less dependent on pesticides, herbicides and
other chemicals that can be hazardous to the environment and farmers.
The risks of genetic engineering in agriculture are outlined as follows:
 Health-related risks-risk of introducing allergens and toxins to the naturally safe food,
which can cause unusual immune reactions.
 Environmental-related risks-may accidentally result in organisms with new genetic
make ups, transgenic crops might cross pollinate creating another variety with
undesirable effects on the environment.