Gene Technology Chapters 11 & 13

Gene Expression 0 Genome 0 Our complete genetic information 0 Gene expression 0 Turning parts of a chromosome “on” and “off”

Gene Expression 0 Uncoiled chromosomes are called euchromatin 0 We have two parts to our genes 0 1. Introns 0 Transcribed but not translated 0 Cut out of mRNA before leaving nucleus 0 2. Exons 0 Transcribed and translated 0 Codes for a protein

Transcription 0 DNA  mRNA 0 After mRNA has been made in the nucleus 0 Introns are spliced out of the mRNA 0 Exons bind together 0 Addition of 5’ cap and poly A tail

Gene Regulation 0 Similar to bacteria except out genome is much larger and more complex 0 98% of our DNA does not code for a protein 0 Each person has a specific number of non-coding regions between exons 0 Called VNTR (Variable Number Tandem Repeats) 0 Nonsense repeats in tandem

DNA Identification 0 Used to identify criminals in a crime scene or to see family relation 0 Four steps to use DNA identification 0 1. Isolate DNA (make copies if small sample) 0 2. Cut DNA in fragments that are known VNTR areas 0 3. Sort DNA by size (using technology) 0 4. Compare size fragments to known samples

How to Make DNA Copies 0 Process called PCR 0 Technology where a small DNA sample can be amplified to many copies for analysis

PCR Steps 0 1. Add sample of DNA, DNA polymerase enzyme, free nucleotides (to make new strands with) and heat sample 0 The heat will act like helicase and separate the strands of DNA

PCR Steps 0 2. Cool sample down so primers can be added to DNA template strands

PCR Steps 0 3. DNA polymerase attaches to primers and adds nucleotides to rest of DNA template strands

PCR Steps 0 4. Two new strands are made  repeat process until enough DNA sample

Cutting DNA 0 Technology that cuts long strands of DNA 0 Biologists use restriction enzymes in order to cut the DNA 0 Biological scissors 0 Restriction enzymes can recognize specific sequences and only cut in certain areas of DNA

Cutting DNA 0 Sometimes when restriction enzymes cut DNA they leave an overhang 0 Creates “sticky” ends where you can then add recombinant DNA 0 Used to input DNA from other organisms into a genome hill.com/olcweb/cgi/pluginpop.cgi?it=swf::535::535::/sites/dl/free/ /120078/bio37.swf

Gel Electrophoresis 0 Technology that separates DNA fragments by size in a gel to compare to known samples

Gel Electrophoresis 0 How to run a gel: 0 1. DNA sample goes through restriction enzymes to break into fragments of known VNTRs 0 2. Each DNA sample (now cut up) gets added into its own chamber well

Gel Electrophoresis 0 3. Electric current is run through the gel for a specific amount of time 0 DNA is negatively charged 0 End of gel is positively charged 0 When current runs, the DNA fragments move towards the end of the gel

Gel Electrophoresis 0 4. DNA is transferred to a nylon membrane where probes are added 0 Probes bind to complementary DNA

Gel Electrophoresis 0 5. X-ray film exposes membrane 0 This creates a band pattern that is unique to each individual 0 Called a “bio fingerprint” 0 You can create a permanent copy of results if needed to file

Gel Electrophoresis 0 How to read results:

Recombinant DNA 0 Genetic engineering: modifying a genome of living cell 0 When you combine two DNA strands from different organisms it is then called recombinant DNA

Cloning 0 Clone 0 Exact copy of DNA, a cell or an organism 0 Clones can be created by inserting DNA into vectors 0 Vectors are organisms that can replicate itself 0 Ex: bacteria, yeasts

Cloning 0 1. Egg cells are extracted from one organism and the nucleus is removed 0 Nucleus removed because the DNA of the organism we want needs to fuse into the egg 0 Cells from organism we wish to clone are removed

Cloning 0 2. Desired organisms cell is placed next to egg cell and electric shock fuses the two cells into one 0 This triggers the new embryo to begin to divide and develop

Cloning 0 3. Developing embryo is implanted in a surrogate mother and after incubation period is over, a new baby organism is born with the exact same genetic information as original organism

Vaccines 0 Substance containing all or part of a harmless strain of a pathogen 0 This gets introduced to our body and we build an immunity for it creating a defense system against the pathogen called antibodies 0 DNA vaccine: vaccine containing genes from pathogen but will not cause infection

Agricultural Applications 0 Made plants more tolerable to our environment 0 Resistance to weeds 0 Added genes that would be harmful to insects and pests 0 Increase nutritional value to some plants 0 Ex: adding vitamin A to rice in Asia – food – animalshttp://