6.3 Manipulating genomes Flashcards
(32 cards)
What method do we use to sequence genes?
Sanger sequencing
What components required to sequence genes?
DNA polymerase, free nucleotides, modified nucleotides called terminators (A, T, C, or G), and lots of ssDNA.
Outline the process of sanger sequencing
-DNA polymerase, terminator nucleotides (A, T, C, or G), and free nucleotides are added to the sequencing machine
-Complimentary bases form hydrogen bonds with eachother and are bonded together with phosphodiester bonds by DNA polymerase
-If a terminator nucleotide is used, the synthesis will stop
-Strands of DNA can be ordered in length and the last base (of the terminator nucleotide) can be read to determine the sequence in the DNA.
What is a nucleoside?
JUST the deoxyribose and the base (not phosphorylated)
Define bioinformatics
Big computer storage bases with lots of genetics that can be used to compare between species etc
What can gene sequencing be used for?
- Comparing genotypes and phenotypes
- Understanding variation between individuals
- Predicitng amino acid sequences of proteins
Why is methylation interesting?
Methylation plays a large part in the regulation of gene expression within organisms
This can help researchers understand the development of some diseases
What is synthetic biology?
Science that is focused on the desingning and building useful biological systems that store and process info.
What are the uses of synthetic biology?
- Information storage (biologists can store computer information onto a strand of DNA- one guy put the whole of william shakespear’s work onto a gene)
- Production of medicines (eg insulin)
- Novel proteins (eg a variant of Hb that doesn’t bind to CO)
- Nanotechnology
How was early DNA profiled?
- DNA obtained (e.g via swab)
- DNA digested by restriction enzymes and cut into smaller fragments
- fragments separated by Gel electrophoresis
- Produces banding that can be compared to other samples
What is different about modern DNA profiling compared to the original way
- old way uses polymorphism: takes way too long
- now we use short tandem repeats: STRs are still polymorphic but allele number is small.
- 13 STRs are sequenced and between 5-20% have each one so it’s easier to identify similarities in genes
What are the applications of DNA profiling?
- forensics (identify criminals or victims)
- maternity & paternity tests
- analysis of disease
Describe the steps of PCR
- DNA is denatured at 94 degrees
- Primers are annealed at 68 degrees
- Taq polymerase binds and catalyses the addition of free nucleotides to DNA strands 5’ to 3’ at 72 degrees
- New double strands are formed
- Cycle begins again
Name the applications of PCR
- Tissue typing for transplants
- Detection of oncogenes
- Detecting mutations
- Identifying viral infections
- Monitoring spread of diease
Outline the steps of gel electrophoresis
- DNA is digested with restriction enzymes that cut it up into smaller fragments
- DNA is dyed
- DNA fragments added to well
- Electricity conducted over the plate
- Negative charge of phosphates means that fragments travel towards anode
- Smaller means they move faster & further
How would you separate proteins?
It’s basically the same thing but SDS equalises surface charge of molecules, allowing proteins to separate as they move through the gel.
What is a DNA probe? What are they used for
small section of ssDNA that is complimentary to the DNA being investigated
Can be used to…
- locate gene required for genetic engineering
- identify presence of specific allele in a disease
How are DNA probes marked?
radioactive or fluorescent marker
What are microarrarys used for?
Detecting the presence of mutated alleles
Describe the process of genetic engineering
- Gene identified
- DNA cut from gene using restriction endonuclease
3.Plasmid also cut using R.E - R.E leaves sticky ends
- Gene inserted into plasmid (using DNA ligase to join the sticky ends) forming recombinant DNA
- Plasmid is inerted into the vector via electroporation (transformation)
- the vector clones
What are some ethical pros and cons surrounding genetic manipulation of microorganisms
- GM microorganisms can make insulin to treat people
-microorganisms could escape and transfer markers for antibiotic resistance
What are some ethical pros and cons surrounding genetic manipulation of plants
- GMO to produce pesticides to increase yield at harvest
- toxic to some insects (butterflies) that pollenate the plants
What are some ethical pros and cons surrounding genetic manipulation of soya beans?
- resistant to herbicides
- create ‘super weeds’
What are some ethical pros and cons surrounding genetic manipulation of golden rice?
- fortified with essential vitamins
- more pricey for farmers to buy
