applications of gene sequencing Flashcards
genome sequencing has made it possible for scientists to …..
- compare entire genomes of members of the same species and different species
- understand evolutionary relationships
- improve classification of species
state 5 ways that genome sequencing allows comparisons to be made between genomes
- identify source of infection
- identify antibiotic resistant bacteria
- track spread of pathogens
- identify regions in the genome for new drugs to target
- analyse genomes of pathogens to compare outbreaks and identify strains (epidemiology)
genome sequencing allows us to predict ….
the proteins that an organism will produce
what is the estimated range for the proteins that humans can make? what does this tell us?
17,000-1 million
- complex relationship between genotype and phenotype
what is synthetic biology?
creation of artificial pathways, organisms or devices, or redesign of natural systems
state 4 examples of synthetic biology
- genetic engineering
- industry
- synthesis of new genes to replace faulty ones
- synthesis of new organisms
what are VNTRs?
variable number tandem repeats
- 95% of human DNA is made up of introns which consist of many VNTRs
the probability of 2 individuals having the same VNTRs is very ….
the more closely related you are, the more …… VNTRs are
low
similar
genetic fingerprinting is the ….. of VNTR ……. this can be used to …….. …… …….. and the ……. …….. within a population
analysis
DNA fragments
determine genetic relationships
genetic variability
state the 7 stages of genetic profiling
- collection
- extraction
- digestion
- separation
- hybridisation
- development
- analysis
describe the first and second stages of genetic profiling
- collection & extraction
- small sample of DNA
- extracted from tissue sample eg from blood or hair follicles
- if sample is small, PCR is used to amplify it
describe the third stage of genetic profiling
- digestion
- restriction endonucleases are added to cut DNA into smaller fragments called satellites
- each type of endonuclease cuts at a specific base sequence called the recognition site
- they cut through both strands of DNA
- if a mixture of endonucleases are used then predictable satellites will be produced
describe the fourth stage of genetic profiling
- separation
gel electrophoresis
- DNA samples are loaded into small wells in agar gel
- the gel is placed in a buffer liquid with an electrical voltage applied
- DNA is negatively charged so samples move through gel towards positive end
- agar creates resistance and smaller DNA moves faster and further
- this separates different lengths of DNA
- alkaline is added to separate the double strands
- the single strands are transferred onto a membrane in a process called southern blotting
describe the fifth stage of genetic profiling
- hybridisation
- DNA probes are short, single stranded pieces of DNA complementary in base sequence to VNTRs
- probes are radioactively or fluorescently labelled
- different DNA probes are mixed with the single stranded DNA VNTRs on the agar gel for them to bind
- the VNTRs hybridise and form hydrogen bonds with probes
describe the sixth stage of genetic profiling
- development
- agar gel shrinks and cracks as it dries
- VNTRs and DNA probes are transferred to a nylon sheet
- nylon sheet is exposed to x rays or UV light to visualise the position
