Applications of genetics

Cloning IVF - in

vitro fertilisation

Stem cells

Genetic fingerprinting

Genetic engineering

Human genome project

Gene therapy

IVF

•hormones trigger ovulation - collected by ultrasound and tube

•male sperm ejaculated and stored in nutrient solution

• male sperm + oocyte into petri dish (100,000 :1) or sperm injected into oocyte

• three days development of embryos

• two implanted in uterus

ISSUES:

What happens to unused embryos? - Stem cell research?freeze in liquid nitrogen for later? Destroy? Donate to others?

Cloning

Plants Animals

Production of genetically identical organisms

micropropagation

Totipotent - differentiated adult cells give rise to different cells

Cut meristem (tip/root areas) or length from shoot cut into small areas = explants sterile, aerated nutient (agar)used callus - mass of undifferentiated ce growth hormones - shoots then roots

transplant into sterile soil

Embryo cloning - IVF, embryo splitting, surrogates

Nuclear transplants - donor cells taken (provide diploid nucleus) unfertilised egg (haploid) from recipient cells fused - egg cell programmed to produce embryo

developing embryo implanted = clone of donor

Stem cells

Undifferentiated cells which divide to give rise to cells that can become specialised

Source = bone marrow; embryonic cells.; umbilical cells

Adult tissue repair/replacement e.g. skin damage, blood cells, respiratory/digestive system linings

Medical research and treatments e.g. virus growth for vaccines (e.g. flu), monoclonal antibodies

Tissue engineering e.g. growth of skin for burns victims, cartilage, blood vessels

Therapeutic use in medicine e.g. use of a patients own cells to grow organs e.g. pancreas for diabetics, heart - better than transplants (no rejection); insertion into the brain (Parkinson’s/Alzheimer’s)

Cells can be grown in labs with growth factors controlled (similar to cloning Dolly)

Ethics - use of embryos, potential of human cloning

Genetic modification

Donor DNA

plasmid from bacterium/ vector

restriction endonucleases ; sticky ends

DNA ligases; splicing

recombinant DNA

cloning

Antibiotic resistance marker genes

fermentors - fitltration and purification

GM crops - transgenic plants e.g. herbicide resistance in soya plants; delayed ripening in tomatoes

Inserted by bacteria

Products used in medical treatment e.g. insulin, growth

hormones

Gene therapy (see later)

Reverse transcription to produce specific DNA for insertion: mRNA -> cDNA-> DNA

reverse transcriptase DNA polymerase

Issues: -benefits crops, medical treatments, products not made by other methods. Release into the environment of potential pathogens, resistance into weeds/pathogens,interactions with other genes, ethics e.g. the right to tamper with genotypes in future

Human genome project

Identification of the 25,000 genes (1990-2003)

Use of markers to identify base sequences of normal genes

Identification of mutated genes which may cause genetic diseases e.g. alzheimer’s, CF, diabetes, cancers - establishing effects (diagnosis)

Identification of individuals carrying the genes : pre-implantation, prenatal, new-born, pre-symptomatic, carriers (pre-conception)

Manufacturing of missing proteins/ designer drugs - genetic engineering

Somatic cell therapy germ cell therapy

Insertion of genetic material into affected cells e.g. cystic fibrosis sufferers respiratory cells

Insertion of corrective genes into eggs - can be inherited

Use of liposomes - enter via the phopholipid bilayer

Use of viruses as vectors

Genetic engineering to extract genes for producing missing proteins

Issues -

Genetic counselling

Genetic screening

Which genes should this be used for?

Abortions to avoid passing on the gene?

Gene therapy

Genetic fingerprinting

Uses - forensic science (identification of criminal), paternity cases, identification of species, evolutionary relationships

Restriction endonucleases non-functional DNA = HVR/STR different lengths (unique)electrophoresis - -ve so move to +ve (smallest move fastest) nylon membrane- Southern blotting radioactive/ chemi-luminescent probes X-ray filmsautoradiograph -> genetic fingerprint

DNA source e.g white blood cells

PCR - manufacture of multiple copies DNA replication DNA polymerase short DNA pieces = primers (signal to enzymes)target DNA heated to 95°Cseparate strandscooled to 55°C - primers join complementary bases heat to 70°C - enzyme polymerises second strandrepeat

Issues:-storage, access,privacy