BIOTECHNOLOGY AND GENETIC ENGINEERING

Stem cell researchGMO & Cloning, Views for and against genetic engineeringDihybrid crossingsMutations in mitochondrial DNA – tracing female ancestry

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WHAT IS BIOTECHNOLOGY?

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BIOTECHNOLOGY - DEFINITION

(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

GENETIC ENGINEERING

Also called genetic modification, is the direct manipulation of an organism's genome using biotechnology.

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An organism that is generated through genetic engineering is considered to be a genetically modified organism (GMO).

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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WHAT IS GENETIC ENGINEERING?

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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GENETIC ENGINEERING TECHNIQUES

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.

GENETIC ENGINEERING TECHNIQUES

Enzymes used in laundry detergentMedicines 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 ENIGINEERINGDISADVANTAGES 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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Disadvantages……..continued

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 escapeand 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

ADVANTAGES….Continued 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 valueof

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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WHAT ARE STEM CELLS?

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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In mammals, there are two broad types of stem cells:

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.

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.16

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REGENERATIVE SKIN

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SOURCES OF STEM CELLS

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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SOURCES OF STEM CELLS……

Stem cells can also be taken from umbilical cord blood just after birth.

Of all stem cell types, adult harvesting involves THE LEAST RISK.

Waar kry jy stamselle?

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USES OF STEM CELLS

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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STEM CELL THERAPY

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ETHICS

Cloning

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Clo

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Cloning

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Roslin Institute, Edinburgh

Dolly and first born lamb, Bonnie.

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WHAT IS CLONING?

The term, “cloning,” describes several different processes of making identical copies of biological material.

Why is cloning important? Because it has the potential to treat a wide range of diseases by generating “self ” tissues.

CLONING

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. 28

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THE CLONING OF DOLLY

Somatic Cell Nuclear Transfer (SCNT):Dolly—The First True Clone (1997)

Breast Cell (udder) (six-year-old Sheep)

Get the nucleus

Empty Egg Cell

+

Cloned Sheep!

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Number of successfully

reconstructed eggs

Number of reconstructed eggs that were able to be implanted in

pseudo-pregnant sheep

Number of cloned sheep

actually born

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SIGNIFICANCE OF DOLLY

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.

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? 32

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INDEPENDENT ASSORTMENT

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INDEPENDENT ASSORTMENT

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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Mendel could only formulate this after performing dihybrid crosses

DIHYBRID CROSS: A Genetic cross that

differs in TWO TRAITS e.g. Height in Plants and Seed colour

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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DIHYBRID CROSSING 

Alleles for different traits are distributed to sex cells (& offspring) independently of one another.

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GENOTYPES

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)

Genotypes of parents: LlGg and LlGg (both heterozygous)

Phenotypes of parents: both tall plants with green seeds

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GENOTYPES AND GAMETES

Genotypes of parents:LlGg x LlGg GAMETES: write as follows: 1 and 3,

1 and 4; then 2 and 3, 2 and 4: LG Lg lG lg (both parents)

Then do crossing in PUNNETT

WORK STEP BY STEP AND SYSTEMATICALLY

LG Lg lG lgLG LLGG LLGg LlGG LlGgLg LLGg LLgg LlGg LlgglG LlGG LlGg llGG llGglg LlGg Llgg llGg llgg

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WORK STEP BY STEP AND SYSTEMATICALLY

LG Lg lG lgLG LLGG LLGg LlGG LlGgLg LLGg LLgg LlGg LlgglG LlGG LlGg llGG llGglg LlGg Llgg llGg llgg

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WORK STEP BY STEP AND SYSTEMATICALLY

LG Lg lG lgLG LLGG LLGg LlGG LlGgLg LLGg LLgg LlGg LlgglG LlGG LlGg llGG llGglg LlGg Llgg llGg llgg

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Check genotypes and phenotypes

LG Lg lG lgLG LLGG LLGg LlGG LlGgLg LLGg LLgg LlGg LlgglG LlGG LlGg llGG llGglg 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

PHENOTYPES:

GENOTYPES PHENOTYPES LLGG (1) tall, green (1) LLGg (2) tall, green (2) LlGG (2) tall, green (2) LlGg (4) tall, green (4) LLgg (1) tall, yellow (1) Llgg (2) tall, yellow (2) llGG (1) short, green (1) llGg (2) short, green (2) llgg (1) short, yellow (1)

9

3

3

1

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TO SUM UP:

Tall, green = 9Tall, yellow = 3Short, green = 3Short, yellow = 1

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MUTATIONS IN MITOCHONDRIAL DNA 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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MUTATIONS IN MITOCHONDRIAL DNA

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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