Genome projects and gene technologies Flashcards
Outline the importance of genome sequencing projects
- Shortcuts
- Find genes more easily
- Allows early intervention medically
- Evolutionary links
Describe the nature of the proteome.
- All proteins produced by the genome
- Certain cells produce certain proteins
- Non-coding DNA
- All proteins produced in a given type of cell
Describe how to determine the genome and proteome of simple organisms
- Prokaryotic DNA is circular, no histones or introns
- Knowledge of exploiting genes to cure diseases
- Bioinformation
- Whole genome shotgun
Describe how to determine the genome and proteome of complex organisms
- Complex organisms have much more DNA
- Humans have introns
- Whole genome shotgun sequencing
What is recombinant DNA technology?
It involves the transfer of fragments of DNA from one organism to another. Since the genetic code is universal the transferred DNA can be translated within cells of the transgenic organism.
How can you isolate a DNA fragment?
- Reverse transcriptase
- Restriction endonuclease
How is reverse transcriptase used in DNA isolation?
- Converts mRNA to DNA (like in HIV)
- mRNA is easier to obtain than DNA
- Doesn’t involve introns
- Produces complementary DNA (cDNA)
How are restriction endonucleases used in DNA isolation?
- Fragments DNA in specific places (base sequence)
- Palindrome sequences
- Sticky ends
How can you amplify a DNA fragment?
- In vivo
- In vitro
How is DNA amplified in vivo?
- Inside a host, e.g. bacteria
- DNA is inserted into the host with the addition of promoter and terminator regions
- Restriction enzyme cuts plasmid and DNA ligase inserts DNA into plasmid (vectors)
- In order to identify whether the cell was transformed an antibiotic resistance gene or bioluminescence gene (marker genes) is also inserted to the plasmid and checked if they are being expressed.
How is DNA amplified in vitro?
- Inside a lab, in glass
- Polymerase Chain reaction
Describe the polymerase chain reaction
- Denaturation using high temperatures
- Annealing using DNA primers (nucleotides) and cool down
- Extension of DNA
- Exponential amplification
Name some uses of recombinant DNA
- Food resistant to pests
- GM cottons
- Vaccines and medicine
- Insulin
- Enzymes
What moral issues surround the use of recombinant DNA technology?
- Animal testing (transgenic animals)
- ‘Unnatural’
What is somatic therapy?
- Altering alleles in body cells
- using a harmless virus: gene added to plasmid and virus inhaled
- using liposomes: phospholipid bilayer, able to fuse with membrane by endocytosis
What is germ-line therapy
Altering alleles in gametes- illegal
What are the advantages of gene therapy?
- Easy to administer
- Avoids terminal disease
- Harmless to the person
- Could prolong life
Disadvantages of gene therapy?
- Targeting cells is difficult
- Can’t cure diseases
- Requires multiple treatments
What are DNA probes?
Complementary, single stranded markers on DNA used for identification, radioactively labeled
What is DNA hybridisation?
Hybridisation of different DNA to identify mutations. Involves a combination of strands of DNA to identify similarities and evolutionary links
What is genetic counselling?
- Advising patients of specific genetic risks and giving them options on how to proceed
What is personalised medicine?
Medication targeted towards people depending on their DNA. Allows for accurate prescription and diagnosis
What are VNTRs?
Variable number tandem repeats, i.e., repeats in non-coding DNA
What are the uses of genetic fingerprinting?
- Forensic investigations
- Checking breeding
- Identification of criminals
- Wildlife protection
- Medical diagnosis
What are the steps in genetic fingerprinting?
- Extraction
- Digestion
- Separation
- Hybridisation
- Development
What does extraction involve in genetic fingerprinting?
- E.g. through a drop of blood
- PCR
What does digestion involve in g.f?
Using specific restriction endonucleases to cut specific DNA sequences
What doe separation involve in g.f?
Using gel electrophoresis to separate the DNA fragments by size
What does hybridisation involve in g.f?
DNA probes are used to bind to the DNA under specific conditions
What does development involve in g.f?
X-ray film is put over a nylon membrane. Radiation from the probes allows the position of the fragments to be seen after gel electrophoresis.
