Genetic engineering involves manipulating DNA for practical applications such as DNA sequencing, creating transgenic organisms, and DNA fingerprinting. Key genetic engineering tools include PCR to make copies of DNA, restriction enzymes to cut DNA into fragments, and plasmids to replicate recombinant DNA containing genes from different sources. Gel electrophoresis is used to separate DNA fragments by size, allowing analysis for applications like DNA fingerprinting, paternity testing, and determining which organisms are transgenic. Cloning creates genetically identical organisms like Dolly the sheep through transferring donor cell nuclei into egg cells.

1. Genetic Engineering
Biology 163
Unit 5 DNA and
Genetic Engineering

2. What is Genetic Engineering?
Manipulating DNA for practical purposes:
– DNA sequencing and the Human Genome
– Transgenic organisms have many applications
in agriculture
– DNA fingerprinting used in forensics

3. Genetic Engineering Tools: PCR
Polymerase chain reaction (PCR) uses DNA
polymerase to make many copies of DNA
Gives scientists enough DNA to work with!

4. Genetic Engineering Tools:
Restriction Enzymes
Proteins which
recognize and cut
specific base sequences
in DNA
Results in fragments of
DNA with “sticky ends”
First step in many DNA
manipulations

5. Plasmids
Plasmids – circular DNA molecules in many
bacteria

6. Plasmid use in genetic engineering

7. Recombinant DNA and Plasmids
Genes are “spliced” into plasmids
Recombinant DNA –contains DNA from
different sources
Plasmids containing the target gene are
reproduced (cloned) inside bacteria
Used to make various proteins:
– insulin, human growth hormone, pest resistance
proteins in plants

8. Gel Electrophoresis
DNA digested by
restriction enzymes
Power source
Longer DNA
fragments
Shorter DNA
fragments
DNA fragments
are placed in
wells of the gel
Gel
DNA is negatively
charged so it will migrate
to the positive size

9. DNA Fingerprinting
Analysis of gel
electrophoresis to
compare the genomes of
organisms
Used in crime
investigations and
paternity tests

10. Whose kids are these???
Using the gel, determine:
– Which child/children are
the offspring of both mom
and dad?
– Which child/children are
the dad’s child from
another marriage?
– Which child/children are
the dad’s child from
another marriage?
– Which child/children are
adopted?

11. Transgenic Organisms
Organisms containing genes
from other species
Transgenic bacteria produce
growth hormone
Transgenic plants and
animals improving
agriculture

12. Cloning
Making a genetically
identical organism
Potential to use
cloning to treat a
variety of disease

13. How was Dolly the sheep made?
Donor Nucleus
Cells are
fused
Fused Cell
Egg Cell
Nucleus is
removed from
the egg cell
Embryo
Cloned Lamb
Foster Mother