Genome projects
A genome is the entire set of DNA, including all the genes, in an organism
Gene sequencing methods only work on fragments of DNA. So when sequencing an
entire genome of an organism the small pieces are sequences and then put back in order
to give the sequence of the whole genome
Sequencing proteomes
• The proteome of an organism is all the proteins that are made by it.
Simple organisms:
• Simple organisms such as bacteria dont have much non coding DNA
• This means it is relatively easy to determine their proteome from the DNA sequence of
their genome.
• This can be useful in medical research an development, eg identifying the protein
antigens on the surface of disease causing bacteria and viruses can help in the
development of vaccines to prevent the disease
• Being able to determine the proteomes of disease causing bacteria and viruses allows
for pathogens to be monitored during outbreaks of disease, which an lead to better
management of the spread of the infection
Complex organisms
• More complex organisms contain large sections of non coding DNA (introns).
• Also contain complex regulatory genes which determine when the genes that code for
the speci c production of a proteins are switched on or o
• This makes it more di cult to translate their genome into their proteome because it is
hard to locate the sections that code for proteins among the non- coding and regulatory
DNA.
Sequencing methods are continuously updated and have become automated.
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, Making DNA fragments
Recombinant DNA technology allows us to combine genetic material from di erent
sources, the rst step is often making a DNA fragment
Recombinant DNA technology
• Involves transferring a fragment of DNA from one organism to another
• Due to the genetic code being universal (same DNA base triplets code for the same
amino acids in all living things) and because transcription and translation mechanisms
are similar too the transferred DNA can be used to produce a protein in the cells of the
recipient organism
• Organisms that contains transferred DNA are known as transgenic organisms
Methods for making DNA fragments
In order to transfer a gene from one organism to another you rst need to obtain a DNA
fragment containing the target gene.
MEHTOD 1: using reverse transcriptase
• Most cells contain two copies of each gene making it di cult to obtain a DNA fragment
containing the target gene
• However cells that produce the protein coded for by the target gene contain the mRNA
molecules complementary to the target gene ——> therefore the mRNA is easier to
obtain
• mRNA can be used as templates to produce lots of DNA
• Reverse transcriptase makes DNA from RNA template
• DNA produced is complementary DNA (cDNA)
1. mRNA is isolated from cells
2. mRNA mixed with free DNA nucleotides and reverse transcriptase
3. Reverse transcriptase uses mRNA as template to synthesise new strands of cDNA
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A genome is the entire set of DNA, including all the genes, in an organism
Gene sequencing methods only work on fragments of DNA. So when sequencing an
entire genome of an organism the small pieces are sequences and then put back in order
to give the sequence of the whole genome
Sequencing proteomes
• The proteome of an organism is all the proteins that are made by it.
Simple organisms:
• Simple organisms such as bacteria dont have much non coding DNA
• This means it is relatively easy to determine their proteome from the DNA sequence of
their genome.
• This can be useful in medical research an development, eg identifying the protein
antigens on the surface of disease causing bacteria and viruses can help in the
development of vaccines to prevent the disease
• Being able to determine the proteomes of disease causing bacteria and viruses allows
for pathogens to be monitored during outbreaks of disease, which an lead to better
management of the spread of the infection
Complex organisms
• More complex organisms contain large sections of non coding DNA (introns).
• Also contain complex regulatory genes which determine when the genes that code for
the speci c production of a proteins are switched on or o
• This makes it more di cult to translate their genome into their proteome because it is
hard to locate the sections that code for proteins among the non- coding and regulatory
DNA.
Sequencing methods are continuously updated and have become automated.
fi ffi ff
, Making DNA fragments
Recombinant DNA technology allows us to combine genetic material from di erent
sources, the rst step is often making a DNA fragment
Recombinant DNA technology
• Involves transferring a fragment of DNA from one organism to another
• Due to the genetic code being universal (same DNA base triplets code for the same
amino acids in all living things) and because transcription and translation mechanisms
are similar too the transferred DNA can be used to produce a protein in the cells of the
recipient organism
• Organisms that contains transferred DNA are known as transgenic organisms
Methods for making DNA fragments
In order to transfer a gene from one organism to another you rst need to obtain a DNA
fragment containing the target gene.
MEHTOD 1: using reverse transcriptase
• Most cells contain two copies of each gene making it di cult to obtain a DNA fragment
containing the target gene
• However cells that produce the protein coded for by the target gene contain the mRNA
molecules complementary to the target gene ——> therefore the mRNA is easier to
obtain
• mRNA can be used as templates to produce lots of DNA
• Reverse transcriptase makes DNA from RNA template
• DNA produced is complementary DNA (cDNA)
1. mRNA is isolated from cells
2. mRNA mixed with free DNA nucleotides and reverse transcriptase
3. Reverse transcriptase uses mRNA as template to synthesise new strands of cDNA
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