Stem cell research
GMO & Cloning,
Views for and against genetic engineering
Dihybrid crossings
Mutations in mitochondrial DNA – tracing female
ancestry
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 (Technological application) is the
use of living systems and
organisms to develop or make
useful products, or to make or
modify products or processes for
specific use
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Also called genetic
modification, is the direct
manipulation of an
organism's genome using
biotechnology.
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 New DNA may be inserted in the
host genome by first isolating and
copying the genetic material of
interest and then inserting this
construct into the host organism.
 Genes may be removed or deleted.
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 Genetic engineering is the
process of modifying an
organism’s genetic composition
by adding foreign genes to
produce desired traits or
evaluate function
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applied in numerous fields including research,
agriculture, industrial biotechnology, and medicine
 Examples
 The first GMOs were bacteria in 1973;
 GM mice were generated in 1974.
 Insulin-producing bacteria were commercialized in
1982
 Genetically modified food has been sold since 1994.
 Glofish, the first GMO designed as a pet, was first
sold in the United States December in 2003.
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Enzymes used in laundry detergent
Medicines such as insulin and human growth
hormone are now manufactured in GM cells,
 Food crops include resistance to certain
pests, diseases, or environmental conditions,
reduction of spoilage, or resistance to
chemical treatments (e.g. resistance to a
herbicide), or improving the nutrient profile
of the crop.
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GENETIC ENIGINEERING
 DISADVANTAGES
 Expensive
 May be difficult for poor people to access 
 Interfere with nature
 Immoral/ we cannot play God/unethical
 Domination of the world food products by
only a few
 companies 
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Loss of biodiversity NOT REDUCES
VARIATION
Potential health impacts
Violation of natural organism’s intrinsic
value(right to independent existence)
Unsure of long term effects
Genes from transgenic organisms could
escapeand be transferred to wild organisms
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GENETIC ENIGINEERING
 ADVANTAGES
Production of medication
Production of resources cheaply
Control pests with specific genes inserted into the
crop
 Selecting the best genes to produce better resistant
crops
 Using specific genes to increase crop yields / food
security
 Selecting genes to increase shelf life of plant products
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Selecting genes that may increase maturation times
to meet the demand
Selecting genes that may decrease maturation
times to meet the demand
Using specific genes to improve nutritional valueof
food for better health
Improve the taste of food
DNA and proteins of transgenic organisms unlikely to
cause problems / transgenic organisms do not
survive easily in wild
Produce organisms that can clean up pollution
Endangered species can be saved
Increases genetic variation
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 Undifferentiated biological cells
that can differentiate into
specialized cells and can divide
(through mitosis) to produce
more stem cells. They are found
in multicellular organisms.
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embryonic stem cells, which are isolated from
the inner cell mass of blastocysts, and
adult stem cells, which are found in various
tissues. In adult organisms, stem cells act as a
repair system for the body, replenishing adult
tissues.
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 In a developing embryo, stem cells
can differentiate into all the
specialised cells —ectoderm,
endoderm and mesoderm — but
also maintain the normal turnover
of regenerative organs, such as
blood, skin, or intestinal tissues.
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1.Bone marrow, which requires extraction by
harvesting, that is, drilling into bone (femur and
pelvis),
 2.Adipose tissue (lipid cells), which requires
extraction by liposuction, and
 3.Blood, which requires extraction from the
donor (similar to a blood donation), and passed
through a machine that extracts the stem cells
and returns other portions of the blood to the
donor.
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 Stem cells can also be taken
from umbilical cord blood just
after birth.
 Of all stem cell types, adult
harvesting involves THE LEAST
RISK.
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Waar kry jy stamselle?
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Adult stem cells are frequently used in medical
therapies, for example in bone marrow
transplantation.
Stem cells can now be artificially grown and
transformed (differentiated) into specialized cell
types with characteristics consistent with cells of
various tissues such as muscles or nerves.
Embryonic cell lines and adult stem cells
generated through therapeutic cloning have also
been proposed as promising candidates for
future therapies.
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Dolly and first born lamb, Bonnie.
Cloning
Clonin
Klonin
Roslin Institute, Edinburgh
loning
loning
Cloning
WHAT IS CLONING?
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The term, “cloning,” describes several
different processes of making identical
copies of biological material.
Because it
has the potential to treat a wide range
of diseases by generating “self ”
tissues.
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In biology, cloning is the process of
producing similar populations of genetically
identical individuals that occurs in nature
when organisms such as bacteria, insects or
plants reproduce asexually.
Cloning in biotechnology refers to processes
used to create copies of DNA fragments
(molecular cloning), cells (cell cloning), or
organisms.
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Somatic Cell Nuclear Transfer (SCNT):
Dolly—The First True Clone (1997)
Get the nucleus
Breast Cell (udder) (six-year-old
Sheep)
+
Empty
Egg Cell
Cloned Sheep!
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Number of
cloned sheep
actually born
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Number of reconstructed
eggs that were able to be
implanted in pseudopregnant sheep
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Number of
successfully
reconstructed eggs
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The effort showed that genetic material from a
specific adult cell, programmed to express only a
distinct subset of its genes, can be
reprogrammed to grow an entirely new
organism.
Before this demonstration, it had been shown by
John Gurdon that nuclei from differentiated cells
could give rise to an entire organism after
transplantation into an enucleated egg.
However, this concept was not yet
demonstrated in a mammalian system.
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ETHICAL ISSUES
Who will take responsibility for the new
(cloned) individual?
 Outcome on humans still unknown –
ethically unacceptable
 Stem cells are removed from a fertilized
egg (embryo) – thereafter it is destroyed
– Is this ethical?
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 allele pairs separate
independently during the
formation of gametes. This
means that traits are
transmitted to offspring
independently of one another.
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A Genetic cross that differs in
TWO TRAITS e.g. Height in
Plants and Seed colour
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Mendel formulated this principle after
performing dihybrid crosses between plants
that differed in two traits, such as seed colour
and seed shape. After these plants were
allowed to self-pollinate, he noticed that the
same ratio of 9:3:3:1 appeared among the
offspring. Mendel concluded that traits are
transmitted to offspring independently
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Alleles for different
traits are distributed to
sex cells (& offspring)
independently of one
another.
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GENOTYPES: 2 CHARACTERISTICS (TRAITS)
crossed e.g. Height of plants and colour of
seeds.
 Tall plants (L) and short plants (l)
 Green seeds (G) and yellow seeds (g)
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Genotypes of parents: LlGg and LlGg (both
heterozygous)
Phenotypes of parents: both tall plants with
green seeds
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Genotypes of parents: LlGg x LlGg
GAMETES: write as follows: 1 and 3, 1 and 4;
then 2 and 3, 2 and 4:
LGLg lG lg (both parents)
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Then do crossing in PUNNETT
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LG
Lg
lG
lg
LG
LLGG
LLGg
LlGG
LlGg
Lg
LLGg
LLgg
LlGg
Llgg
lG
LlGG
LlGg
llGG
llGg
lg
LlGg
Llgg
llGg
llgg
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LG
Lg
lG
lg
LG
LLGG
LLGg
LlGG
LlGg
Lg
LLGg
LLgg
LlGg
Llgg
lG
LlGG
LlGg
llGG
llGg
lg
LlGg
Llgg
llGg
llgg
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LG
Lg
lG
lg
LG
LLGG
LLGg
LlGG
LlGg
Lg
LLGg
LLgg
LlGg
Llgg
lG
LlGG
LlGg
llGG
llGg
lg
LlGg
Llgg
llGg
llgg
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LG
Lg
lG
lg
LG
LLGG
LLGg
LlGG
LlGg
Lg
LLGg
LLgg
LlGg
Llgg
lG
LlGG
LlGg
llGG
llGg
lg
LlGg
Llgg
llGg
llgg
GENOTYPES: LLGG (1)
LLGg (2) LlGG (2) LlGg (4) LLgg (1)
Llgg (2) llGG (1) llGg (2) llgg (1) = 9 types
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GENOTYPES
LLGG (1)
LLGg (2)
LlGG (2)
LlGg (4)
 LLgg (1)
 Llgg (2)
 llGG (1)
 llGg (2)
 llgg (1)
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PHENOTYPES
tall, green (1)
tall, green (2)
tall, green (2)
tall, green (4)
tall, yellow (1)
tall, yellow (2)
short, green (1)
short, green (2)
short, yellow (1)
9
3
3
1
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 Tall, green = 9
 Tall, yellow = 3
 Short, green = 3
 Short, yellow = 1
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USEFUL: Trace genetic linkages
Sperms + Ova contain also MITOCHONDRIA
WITH DNA AND GENES
mtDNA of sperm cell does NOT fuse with
that of the egg cell
mtDNA is handed down from mother to child
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By following mutant nucleotides in mtDNA,
we follow our female line of descent
Mutations take place at faster rate – making
it easier to trace female lineage
mtDNA is handed down from mother to child
By following mutant nucleotides in mtDNA,
we follow our female line of descent
Mutations take place at faster rate – making
it easier to trace female lineage
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