Changing the living world
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Changing the living world. How we change the living world…. Selective breeding: crossing organisms with desired traits to produce the next generation. How we change the living world…. Hybridization: crossing dissimilar organisms to get the best of both. How we change the living world….

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Changing the living world

Changing the living world


How we change the living world

How we change the living world…

Selective breeding: crossing organisms with desired traits to produce the next generation.


How we change the living world1

How we change the living world…

Hybridization: crossing dissimilar organisms to get the best of both.


How we change the living world2

How we change the living world…

Inbreeding: continually breeding individuals with similar characteristics.


Changing the living world

GENETIC ENGINEERING


Genetic engineering vocab

Genetic engineering vocab

  • Recombinant DNA- nucleotide sequences from two different sources to form a single DNA molecule.

  • Transgenic organism – contains a gene from another organism, typically a different species

  • Genetically modified organisms (GMOs)- organisms that have acquired one or more genes by artificial means.


Changing the living world

Figure 12.1


Changing the living world

Genetic Engineering

  • Genetic engineering: The process of manipulating genes for practical purposes.

  • Genetic engineering may involve building recombinant DNA

DNA made from two or more different organisms.


Changing the living world

Steps in a Genetic Engineering Experiment

Step 1 Isolate Target DNA and plasmid and cut with restriction enzymes

Step 2 Recombinant DNA is produced.

Step 3 Gene cloning: the process by which many copies of the gene of interest are made each time the host cell reproduces.

Step 4 Cells undergo selection and then are screened.


Steps in a genetic engineering experiment

Steps in a Genetic Engineering Experiment

Step 1 The DNA from the organism containing the gene of interest and the vector are cut by restriction enzymes.

A vector is an agent that is used to carry the gene of interest into another cell

Commonly used vectors: viruses, yeast, and plasmids.

circular bacterial DNA


Changing the living world

Plasmids

Bacterial

chromosome

Remnant of

bacterium

Colorized TEM

Figure 12.7


Changing the living world

Isolate

plasmids.

Bacterial cell

Plasmid

Figure 12.8-1


Changing the living world

Isolate

DNA.

Cell containing

the gene of interest

Isolate

plasmids.

Bacterial cell

Plasmid

DNA

Figure 12.8-2


Changing the living world

Cut both DNAs

with same

enzyme.

DNA fragments

from cell

Isolate

DNA.

Gene of

interest

Other

genes

Cell containing

the gene of interest

Isolate

plasmids.

Bacterial cell

Plasmid

DNA

Figure 12.8-3


Changing the living world

Cut both DNAs

with same

enzyme.

DNA fragments

from cell

Isolate

DNA.

Gene of

interest

Other

genes

Mix the DNAs and

join them together.

Gene of interest

Cell containing

the gene of interest

Isolate

plasmids.

Bacterial cell

Recombinant DNA plasmids

Plasmid

DNA

Figure 12.8-4


Changing the living world

Cut both DNAs

with same

enzyme.

DNA fragments

from cell

Isolate

DNA.

Gene of

interest

Other

genes

Mix the DNAs and

join them together.

Gene of interest

Cell containing

the gene of interest

Isolate

plasmids.

Bacterial cell

Recombinant DNA plasmids

Bacteria take up recombinant plasmids.

Plasmid

DNA

Recombinant bacteria

Figure 12.8-5


Changing the living world

Cut both DNAs

with same

enzyme.

DNA fragments

from cell

Isolate

DNA.

Gene of

interest

Other

genes

Mix the DNAs and

join them together.

Gene of interest

Cell containing

the gene of interest

Isolate

plasmids.

Bacterial cell

Recombinant DNA plasmids

Bacteria take up recombinant plasmids.

Plasmid

DNA

Recombinant bacteria

Bacterial clone

Clone the bacteria.

Figure 12.8-6


Changing the living world

Cut both DNAs

with same

enzyme.

DNA fragments

from cell

Isolate

DNA.

Gene of

interest

Other

genes

Mix the DNAs and

join them together.

Gene of interest

Cell containing

the gene of interest

Isolate

plasmids.

Bacterial cell

Recombinant DNA plasmids

Bacteria take up recombinant plasmids.

Plasmid

DNA

Recombinant bacteria

Bacterial clone

Clone the bacteria.

Find the clone with

the gene of interest.

Figure 12.8-7


Changing the living world

Cut both DNAs

with same

enzyme.

DNA fragments

from cell

Isolate

DNA.

Gene of

interest

Other

genes

Mix the DNAs and

join them together.

Gene of interest

Cell containing

the gene of interest

Isolate

plasmids.

Bacterial cell

Recombinant DNA plasmids

Bacteria take up recombinant plasmids.

Plasmid

DNA

Recombinant bacteria

Bacterial clone

Clone the bacteria.

Find the clone with

the gene of interest.

Some uses

of genes

Some uses

of proteins

Gene for pest

resistance

Protein for

dissolving

clots

Protein for

“stone-washing”

jeans

Gene for

toxic-cleanup

bacteria

The gene and protein

of interest are isolated

from the bacteria.

Genes may be

inserted into

other organisms.

Harvested

proteins may be

used directly.

Figure 12.8-8


Restriction enzymes molecular scissors

RESTRICTION ENZYMESmolecular scissors


A closer look cutting and pasting dna with restriction enzymes

A Closer Look: Cutting and Pasting DNA with Restriction Enzymes

  • Recombinant DNA is produced by combining two ingredients:

  • A bacterial plasmid

  • The gene of interest

  • How do we cut them?

    • Using restriction enzymes: bacterial enzymes which cut DNA at specific nucleotide sequences

    • produce pieces of DNA called restriction fragments.

    • Why do you think bacteria contain restriction enzymes?


Changing the living world

Restriction Enzymes are palindromes: the same forward as backwards, like RACECAR.

Examples:

GAATTCCCCGGGAAGCTT

CTTAAGGGGCCCTTCGAA

G AATTCCCC GGGA AGCTT

CTTAA GGGG CCCTTCGA A

Sticky Ends

Blunt End


Changing the living world

Recognition sequence

for a restriction enzyme

DNA

A restriction enzyme cuts

the DNA into fragments.

Restriction

enzyme

Sticky

end

Sticky

end

Figure 12.9-1


Changing the living world

Recognition sequence

for a restriction enzyme

DNA

A restriction enzyme cuts

the DNA into fragments.

Restriction

enzyme

Sticky

end

Sticky

end

A DNA fragment is added

from another source.

Figure 12.9-2


Changing the living world

Recognition sequence

for a restriction enzyme

DNA

A restriction enzyme cuts

the DNA into fragments.

Restriction

enzyme

Sticky

end

Sticky

end

A DNA fragment is added

from another source.

Fragments stick together by

base pairing.

Figure 12.9-3


Changing the living world

DNA LIGASE

  • DNA ligase connects the DNA fragments into one continuous strand (DNA Glue or tape)


Changing the living world

Recognition sequence

for a restriction enzyme

DNA

A restriction enzyme cuts

the DNA into fragments.

Restriction

enzyme

Sticky

end

Sticky

end

A DNA fragment is added

from another source.

Fragments stick together by

base pairing.

DNA

ligase

DNA ligase joins the

fragments into strands.

Recombinant DNA molecule

Figure 12.9-4


Changing the living world

Recognition sequences

DNA sequence

Restriction enzyme EcoRI cuts the DNA into fragments.

Sticky end


Your turn to try

Your turn to try!!


Changing the living world

  • Plasmids:

    • Can easily incorporate foreign DNA

    • Are readily taken up by bacterial cells

    • Can act as vectors, DNA carriers that move genes from one cell to another

    • Are ideal for gene cloning, the production of multiple identical copies of a gene-carrying piece of DNA


Changing the living world

Bacterial cells don’t edit the RNA, so how can they make the correct protein?

Genetic Engineers can eliminate the introns from mRNA and reverse the process, producing a DNA strand that is only the instructions for the protein.

Use Reverse Transcriptase


Changing the living world

Cell nucleus

Exon

Exon

Exon

Intron

Intron

DNA of

eukaryotic

gene

Transcription

Test tube

Figure 12.11-1


Changing the living world

Cell nucleus

Exon

Exon

Exon

Intron

Intron

DNA of

eukaryotic

gene

Transcription

RNA

transcript

Introns removed and

exons spliced together

mRNA

Test tube

Figure 12.11-2


Changing the living world

Cell nucleus

Exon

Exon

Exon

Intron

Intron

DNA of

eukaryotic

gene

Transcription

RNA

transcript

Introns removed and

exons spliced together

mRNA

Test tube

Isolation of mRNA from

cell and addition of

reverse transcriptase

Reverse

transcriptase

Figure 12.11-3


Changing the living world

Cell nucleus

Exon

Exon

Exon

Intron

Intron

DNA of

eukaryotic

gene

Transcription

RNA

transcript

Introns removed and

exons spliced together

mRNA

Test tube

Isolation of mRNA from

cell and addition of

reverse transcriptase

Reverse

transcriptase

Synthesis of cDNA

strand

cDNA strand

being synthesized

Figure 12.11-4


Changing the living world

Cell nucleus

Exon

Exon

Exon

Intron

Intron

DNA of

eukaryotic

gene

Transcription

RNA

transcript

Introns removed and

exons spliced together

mRNA

Test tube

Isolation of mRNA from

cell and addition of

reverse transcriptase

Reverse

transcriptase

Synthesis of cDNA

strand

Synthesis of second DNA

strand by DNA polymerase

cDNA strand

being synthesized

cDNA of gene

without introns

Figure 12.11-5


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