Chapter 20
DNA Technology and Genomics
Chapter 20
DNA Technology and Genomics
Viruses have restriction enzymes
to attack and destroy invading
viral DNA.
Restriction enzymes cut DNA at
specific nucleotide sequences
leaving “sticky ends.”
DNA ligase can seal these ends,
making recombinant DNA.
Chapter 20
DNA Technology and Genomics
Restriction fragments can be put
into plasmids.
Gene cloning occurs when cells
containing these plasmids
reproduce.
Genes of interest are marked
with a radioactive DNA probe.
Chapter 20
DNA Technology and Genomics
If a gene is inserted next to a
promoter, the bacteria becomes
an expression vector.
Eukaryotic chromosomes allow
for bigger segments of DNA.
Eukaryotic cells can also process
polypeptides into proteins.
Chapter 20
DNA Technology and Genomics
Chopping up the whole genome of
an organism produces many DNA
fragments containing many genes.
Often, the researcher will save all of
them, either in bacteria or in viruses.
These collections of bacterial clones
are called genomic libraries.
Chapter 20
DNA Technology and Genomics
Polymerase chain reaction (PCR)
uses DNA polymerase to clone DNA
in vitro.
In vitro = in a test tube
In vivo = in a living organism
Chapter 20
DNA Technology and Genomics
DNA Fingerprinting
Human DNA contains lots of noncoding
sequences that serve no purpose.
This “junk DNA” often repeats over and
over.
No two people (except identical twins)
have exactly the same repeats.
Chapter 20
DNA Technology and Genomics
DNA Fingerprinting
Bill’s chromosome:
gene A xxxxx gene B yyy gene C
Bob’s chromosome:
gene A xx gene B yyyyy gene C
Chapter 20
DNA Technology and Genomics
DNA Fingerprinting
Restriction enzymes cut DNA at
specific places.
Bill’s chromosome:
gene A xxxxx gene B yyy gene C
Bob’s chromosome:
gene A xx gene B yyyyy gene C
Chapter 20
DNA Technology and Genomics
DNA Fingerprinting
Restriction enzymes cut DNA at
specific places.
Bill’s chromosome:
gene A xxxxx gene B yyy gene C
Bob’s chromosome:
gene A xx gene B yyyyy gene C
Chapter 20
DNA Technology and Genomics
DNA Fingerprinting
Restriction enzymes cut DNA at
specific places.
Bill’s chromosome:
gene A xxxxx gene B yyy gene C
Bob’s chromosome:
gene A xx gene B yyyyy gene C
Chapter 20
DNA Technology and Genomics
DNA Fingerprinting
Restriction enzymes cut DNA at
specific places.
Bill’s chromosome:
Bob’s chromosome:
Chapter 20
DNA Technology and Genomics
DNA Fingerprinting
Longer fragments travel more
slowly through the gel.
Bill’s chromosome:
Bob’s chromosome:
Chapter 20
DNA Technology and Genomics
DNA Fingerprinting
Bill’s chromosome:
Bob’s chromosome:
Chapter 20
DNA Technology and Genomics
DNA Fingerprinting
Bill’s chromosome:
Bob’s chromosome:
Chapter 20
DNA Technology and Genomics
DNA Fingerprinting
Bill’s chromosome:
Bob’s chromosome:
Chapter 20
DNA Technology and Genomics
Chapter 20
DNA Technology and Genomics
The southern blot
1. Do DNA fingerprinting on an
entire genome.
2. Blot the DNA from the gel to
paper with an alkaline solution.
This denatures the DNA.
3. Hybridize with a radioactive
probe.
Chapter 20
DNA Technology and Genomics
The southern blot
Chapter 20
DNA Technology and Genomics
The southern blot
Chapter 20
DNA Technology and Genomics
RFLPs (“RIF-lips”), or restriction
fragment length polymorphisms, are
differences in homologous
chromosomes that give different
length restriction fragments.
Chromosome walking means finding
where fragments of DNA overlapped
in the genome.
Chapter 20
DNA Technology and Genomics
Genomics is the systematic study of
entire genomes.
Proteomics is the study of all the
proteins encoded by a genome.
Single nucleotide polymorphisms
(SNPs) are useful markers for
studying variation.
Chapter 20
DNA Technology and Genomics
Uses of DNA Technology:
Testing for genetic diseases
Large scale production of drugs
Gene therapy
Forensics
Genetic engineering