M6 Ch12 Manipulating genomes Flashcards
What is genome sequencing?
Genome sequencing is info about gene location and provides evidence for evolutionary links between organisms
What is genetic engineering?
Genetic engineering involves manipulation of naturally occurring processes and enzymes
What are introns?
Introns are non-coding regions of DNA
What is satellite DNA?
Satellite DNA (short-tandem repeats) = short sequences within introns repeated many times that appear at the same point in chromosomes
What is the human genome project? (HGP)
The Human Genome project = international funded venture to sequence 3 billion bases in 20k+ genes of the human genome - corrections and analyses have been added to results over the years
What is DNA profiling?
DNA profiling = producing an image of the patterns in the DNA of an individual - producing patterns assists in identification of individuals and determining family relationships
What are the key processes that undergo DNA profiling?
Key DNA profiling processes:
-PCR (polymerase chain reaction) = amplifies the DNA by replication
-Electropheresis = seperates DNA fragments according to mass
-Hybridisation = probes added to identify fragments
How to produce a DNA profile?
Producing a DNA profile:
1). Extract DNA
2). Undergo PCR and amplification
3). Digest sample (restriction endonucleases) - cut the strands into small fragments at specific sites
4). Electrophoresis
5). Hybridisation (add DNA probes, RNA complentary binds -> radioactive or fluorescent)
What are the uses of DNA profiling?
Uses of DNA profiling:
-Crime scenes - samples
-Child paternity
-Immigration cases that prove/disprove family relationships
-Establish evolutionary relationships
What is PCR? (polymerase chain reaction)
PCR = artificial way of DNA replication -> amplifies DNA, primers added, DNA is heated and cooled so it can seperate and bind together
Describe the process of PCR. (polymerase-chain reaction)
PCR:
1). DNA sample mixed with DNA nucleotides and DNA polymerase
2).Mixture heated to 95 (denaturation) + bonds between strands break
3). Primers added
4). Temp reduced to 55 (annealing) - primers bind and now double stranded
5). DNA polymerase binding to strands
6). Temp at 72 (optimum for polymerase) adding free nucletotides
Why does polymerase not denature in PCR?
Polymerase does not denature because it is extracted from extremophile bacteria -> can cope with high temperature
What are the stages of electropheresis/DNA profiling?
Electropheresis stages:
1). cells broken down to release DNA (small amount -> amplifiy with PCR)
2). DNA cut into fragments using restriction endonucleases
3). Fragments seperates on bases of site using gel electropheresis
-Fragments injected into wella and electric current applied along gel
Why is gel in electropheresis put into alakaline solution?
Gel is puit into alkali solution to seperate double strands into single ones
Results of gel electropheresis/DNA profiling
Results of gel electropheresis/DNA profiling
-DNA negatively charged so it is attracted to positive end of gel
-Shorter DNA fragments move faster than longer fragments
-DNA seperated on basis of size
Hybridisation of DNA profiling
Hybridisation = radioactive or fluorescent DNA probes added to DNA fragments on membrane
-Probes bind to complementary strands under pH and temp conditions
What is DNA sequencing?
DNA sequencing = the process of determining the precise order of nucleotides within a DNA molecule
Stages of DNA sequencing
Stages of DNA sequencing:
1). DNA mixed with primer, DNA polymerase, excess of nucleotides and terminator bases
2). Mixture placed in thermal cycler (96C=seperates strands, 50C=primers anneal to strand)
3). 60C=polymerase builds new strands by adding nucleotides with complementary base to single strand
4). When terminator base added, a strand terminates until all possible chains produced
5). DNA fragments serperated by length in capillary tubes - the fluorescence on terminater bases determine final base of each fragmentq
Benefits of DNA profiling
Benefits of DNA profiling:
-Identification of individuals and family relationships
-use in crime scenes
-proving or disproving immigration cases
Limitations of DNA profiling
Limitations of DNA profiling:
-Can be too dependent on in comparison to other evidence in crime scenes
-Mistakes can be made as it is done on multiple levels
-Potential contamination of DNA samples from other organisms
What is genetic engineering?
Genetic engineering is the manipulation of the genome to achieve a desired outcome
Basic principles= isolating a gene fur a desired characteristic in one organism into another using a suitable vector)
What is meant by transgenic?
Transgenic is an organism carries a gene from one organism - often called a genetically modified organism (GMO)
Process of genetic engineering
Process of genetic engineering:
1 isolating the desired gene 2. Formation of a recombinant DNA 3. Transforming the vector
Isolating the desired menu as the first step of genetic engineering
By restriction endonuclease (DNA profiling) at specific base sequences
Sticky ends = unevenly it DNA where desire gene is easier to insert
Formation y recombinant DNA as the second stage of genetic engineering
Formation o recombinant DNA → plasmid combines with dna to form recombinant DNA → used as vectors as they contain marker genes, allowing scientists to see if bacteria has taken Up the plasmid → restriction endonuclease cuts open plasmid so there are complimentary shiny ends no the DNA fragment → DNA lipase forms phosphodester bands between phosphates + sugar
Process of transformation y vector in genetic engineering
Transformation = plasmid with recombinant dna transformed into host cell → electroporation =electrical current applied no bacteria → membranes became porous + plasmids moves into the cell
What is electroporation?
Electroporation is when an electrical current
Is applied lo bacteria → membranes becomes porous → plasmids into cell → used for genetic engineering
How is electroporation used with eukaryotic cells?
Electroporation can also be used toget DNA fragments directly into eukaryotic cells → passes through porous membrane → fuses with nuclear DNA → however, the current potentially damage membrane
How is genetic engineering used in prokaryotes?
Prokaryotes = gm prokaryotes produces substances eg hormones such as insulin, and antibiotics
How does genetic engineering work with animals?
Gm in animals → membranes are harder to manipulate → but
Animals produce medically important proteins and helps to cure genetic diseases
Describe the process of genetic engineering in plants?
Genetic engineering in plants =
1. Cut leaf
2. Expose leaf to bacteria containing weed and antibiotic resistant gene
3. Allow bacteria to deliver genes to leaf cells
4. Wait for gene altered cells to multiply and form clump (callus)
5. Allow callus to sprout shoots and roots
6. Plants transferred to soil where they develop into fully differentiated plants that are resistant
DNA sequencing projects
DNA sequencing projects - eg HGP = enables scientists to build a collection of sequenced DNA fragments from organism that is then stored and propagated in microorganisms
Benefits of genetically modified microorganisms
Benefits of genetically modified microorganisms:
-developing new medical treatments
-development of gene technology
-medical research
Genetic engineering ethical concerns
Genetic engineering ethical concerns:
-Potentiality of disease outebreak is scientist affected/disease outbreak
Genetic engineering uses
Genetic engineering uses:
-Produce insulin
-Genetic modification of pathogens -> makes them more resistant -> used in military -> biological warfare
GM plants ethics
GM plants ethics:
+ = food security
- = soya - insertion of BT protein poisonous to insects
+/- = herbicide resistence - more used = greater monoculture = susceptibility to disease
+ = medical use
+ = improve nutritional value
What is patenting?
Patenting = can’t use GM crops without patent (paying) - people may not afford it, unable to grow seeds for next yields as crops bought can only be used that year they bought it
GM animals + ethics
GM animals + ethics:
- = more difficult
+ = disease resistance
+ = dna insertion - faster growth - faster bigger yield
- = animal rights - risk of harm
+ = create human proteins
What is somatic cell therapy?
Somatic Cell Therapy:
-Not passed onto future generations
-Needs to be topped up
-Mitosis - original cells with problem replace the new cell - issue passed onto children
-SCT involves altering alleles in target body cells
What is germline cell therapy?
Germline cell therapy:
-Healthy alleles inserted into eggs
-Passed onto future genreations
-Illegals in many countries due to human rights - ethical issues - desirable characteristics
