Describe natural processes of looking at DNA role and structure
DAN strands cut into smaller fragments with restriction endonucleases. Fragments separated by electrophoresis, replicated by polymerase chain reaction (PCR). Analysed to give base sequence, sealed using DNA ligase. DNA probes locate specific sequence
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What does a gene code for and explain coding and non-coding DNA
Genes code for proteins and polypeptides. Most of DNA is non-coding, only a small percent is coding DNA.
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How many base pairs can a sequencing reaction operate on?
750 base pairs.
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How do we get to 750 bp?
Genome must be broken up and sequenced in sections.
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What is the 1st stage of sequencing an organism?
Genomes mappped to identify part of chromosome they are from. Known information used e.e. location of microsatellites.
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What happens after the genome is mapped?
Samples of the genome are sheared (shotgun approach) into smaller sections of 100,000 base pairs.
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What happens to the sections?
They are placed into separate Bacterial Artificial Chromosomes (BAC's).
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Where are they transferred to?
E.coli cells.
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What must be done first in order to sequence a BAC section?
Cells containing specific BAC's are taken and cultured. DNA extracted and restiriction endonucleases cut into smaller fragments.
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What does the use of different restriction enzymes on a number of samples mean?
Different fragment types are produced.
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What happens to these fragments?
They are separated by electrophoresis and sequenced using an automated process.
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What do computer programmes do?
Compare overlapping regions from cuts made by different restriction enzymes to reassemble the whole BAC segment sequence.
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What is comparative gene mapping?
Being able to compare genes for the same proteins across a range of organisms.
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How is comparative gene mapping useful?
Identification of genes for proteins found in many/all organisms shows importance. Comparing DNA of different species shows evolutionary relationships. Modelling effects of changes to DNA can be carried out.
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Applications
Comparing genomes from pathogenic and non-pathogenic organisms can be used to identify genes important in causing disease. Lead to development of new treatments.
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Applications
DNA of individuals can be easily analysed which can reveal mutant alleles or increased risk of diseases.
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Other cards in this set
Card 2
Front
Describe natural processes of looking at DNA role and structure
Back
DAN strands cut into smaller fragments with restriction endonucleases. Fragments separated by electrophoresis, replicated by polymerase chain reaction (PCR). Analysed to give base sequence, sealed using DNA ligase. DNA probes locate specific sequence
Card 3
Front
What does a gene code for and explain coding and non-coding DNA
Back
Card 4
Front
How many base pairs can a sequencing reaction operate on?
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