Advanced Genetics 10.2, 10.3, 4.4

Skin colour video

4.4

Past few decades... PCR to copy DNA into a libraryPCR to copy DNA into a library DNA profilingDNA profiling Mapping the human genomeMapping the human genome Cutting & pasting genes (gene transfer)Cutting & pasting genes (gene transfer) Cloning cells...cloning animals!Cloning cells...cloning animals!

4.4.1 Outline the use of polymerase chain reaction (PCR) to copy and amplify minute quantities of DNA. Very small DNA sample (1 – few cells!) Copies it  millions of copies in a few hours –DNAi video Can use it for analysis or put into library Important in forensics

4.4.2 State that, in gel electrophoresis, fragments of DNA move in an electric field and are separated according to their size. Restriction enzymes chop it up into fragments Fragmented DNA placed into wells of the gel Electrical field Neg. DNA migrates through gel to + electrode Smaller fragments move fastest!

4.4.3 State that gel electrophoresis of DNA is used in DNA profiling. Banding pattern of DNA fragments Match unknown & suspect/victim/parent/etc. “DNA fingerprinting” Similar  probably relatives Exact  exact No match  no match!

4.4.4 Describe the application of DNA profiling to determine paternity and also in forensic investigations. Paternity? Who’s the baby-daddy? Compare mom, dad, baby DNA...more effective than blood-typing? Forensics? Blood samples, etc. Compare crime scene vs victim, suspects, etc. Has been used to re-open old cases & release wrongly imprisoned people! Marine forensics...endangered species, trade items; genetics/evolutionary relationships

4.4.5 Analyse DNA profiles to draw conclusions about paternity or forensic investigations.

4.4.6 Outline three outcomes of the sequencing of the complete human genome – 2003 Sequence of entire genome Now: which are genes, which aren’t, what genes do  map of all loci for all genes on all 23 chromosomes! Library of genetic diseases (treatment, diagnosis) Find beneficial molecules produced in healthy people  new medications –Find gene, copy it, make lots of it Ancestry studies of world population...unity & diversity!

4.4.7 State that, when genes are transferred between species, the amino acid sequence of polypeptides translated from them is unchanged because the genetic code is universal. Donor organism: arctic fish Host organism: tomato How’s it work???? Makes tomatoes more resistant to cold and frost, because makes a natural antifreeze-like protein Genetic code is universal! –ATGC –Same codons  same amino acids  same protein –(unity!)

4.4.8Outline a basic technique used for gene transfer involving plasmids, a host cell (bacterium, yeast or other cell), restriction enzymes (endonucleases) and DNA ligase. Cut, copy, paste! Scissors: restriction enzymes (endonucleases) recognize specific sequence on DNA (4-6 bp), cut the gene of interest & remove it from “donor”

4.4.8Outline a basic technique used for gene transfer involving plasmids, a host cell (bacterium, yeast or other cell), restriction enzymes (endonucleases) and DNA ligase. Cut, copy, paste! Copying = DNA cloning Host cell needed (E. coli or yeast) –Plasmid: small, circular, “extra” DNA in cytoplasm –‘glue’ the desired gene into the plasmid...

4.4.8Outline a basic technique used for gene transfer involving plasmids, a host cell (bacterium, yeast or other cell), restriction enzymes (endonucleases) and DNA ligase. Cut, copy, paste! Remove plasmid from host cell Cut w/restriction endonuclease Add desired gene “ends” match up (gene splicing)

4.4.8Outline a basic technique used for gene transfer involving plasmids, a host cell (bacterium, yeast or other cell), restriction enzymes (endonucleases) and DNA ligase. Cut, copy, paste! DNA LIGASE!  “recombinant plasmid” Can be used as a vector...tool for introducing new gene into an organism’s genome Place vector inside host bacterium, culture, reproduce, copies gene each time, transcribes & translates it also! –Human insulin from E. coli! –No more allergy problems w/cow or pig insulin!

Journal If you had an incurable disease, would you try gene therapy treatment? Watch the video on how it works…… what are your thoughts now?

4.4.9State two examples of the current uses of genetically modified (GM) crops or animals. Artificial genetic change using gene transfer or recombinant DNA **competitive agriculture Crops: Bt corn: genetically engineered to make toxins that kill the bugs that attack it (gene from soil bacterium, Bacillus thuringiensis— able to make the toxin) Flavr Savr tomatoes: ’94-GM to delay rotting/ripening; too costly Saline-tolerant tomatoes: grow in different regions GM Rice: produce beta carotene so no vitamin A deficiencies Possible applications...solve world hunger?!

4.4.9State two examples of the current uses of genetically modified (GM) crops or animals. Animals: Factor IX: transgenic sheep w/gene that codes for this clotting factor; associated w/genetic info for milk production in female sheep, produces the protein in her milk  hemophilia treatment...More resistance to parasites, pre-dyed wool on sheep, show dogs, racehorses,

Discuss the potential benefits and possible harmful effects of one example of genetic modification. Which do YOU agree with? LIST...

Define clone. Group of genetically identical organisms or Group of cells artificially derived from a single parent Resulting cells made using lab techniques

Outline a technique for cloning using differentiated animal cells. Once thought you couldn’t use differentiated cells DOLLY Video clips

Outline a technique for cloning using differentiated animal cells. 1.Donor sheep: somatic cell from udder collected & cultured; nucleus removed from a cell 2.Unfertilized egg from another sheep, nucleus removed 3.ZAP! Electric current fuses the egg cell and nucleus from the cultured somatic cell 4.New cell develops in vitro (similar to a zygote, starts to form an embryo)

Outline a technique for cloning using differentiated animal cells. 5. Embryo placed in womb of surrogate mom sheep 6. Develops normally 7. Dolly! Clone of original donor sheep “Reproductive cloning” because a whole individual is made

Discuss the ethical issues of therapeutic cloning in humans. Therapeutic cloning = making copies of cells, not yet differentiated Embryonic stem cells Ethics...be well-informed, know all sides! Used for: –Growing skin to repair serious burns –Growing new heart muscle to repair... –Growing new kidney tissue to repair kidney failure What about reproductive cloning in humans?