3.5 – Genetic Modification & Biotechnology

PCR – Polymerase Chain Reaction For other techniques, substantial quantities of DNA are necessary PCR is used to make millions of copies of a DNA sample so that other biotechnologies can be done http://highered.mcgraw-hill.com/sites/9834092339/student_view0/chapter18/polymerase_chain_reaction.html

II. Gel Electrophoresis -Used to separate fragments of DNA A. Restriction enzymes (endonucleases) are used to cut up DNA into fragments of varying sizes B. Fragments placed in holes at one end of a slab of charged gel

DNA fragments move through gel towards positive pole (WHY?) Smaller pieces move farther faster than larger pieces (WHY?) creating a banded pattern

DNA Profiling/Fingerprinting A. Match an unknown sample of DNA with a known sample B. If patterns are the same = same person Patterns similar = probably related C. Used for paternity testing, criminal investigations, determining evolutionary and ecological relationships https://www.youtube.com/watch?v=ZAuWYP7rt0A

Cutting and Pasting Genes A. Restriction enzymes (endonucleases) find and recognize a specific sequence of base pairs along the DNA molecule and cut it at specific points B. For pasting a gene, DNA ligase recognizes sticky ends and fuses

V. Gene Transfer AKA gene modification – take a gene out of one organism and place it into a different organism 1. Used to create cold- and pest-resistant crops B. REMEMBER – Universal Genetic Code

Cloning A. Reproductive cloning - Making copies of whole organisms

Therapeutic cloning - Making copies of embryonic/adult stem cells (AKA stem cell research) 1. Its aim is to develop cells which have not yet gone through the process of differentiation

Ethical Issues surrounding therapeutic cloning a. Therapeutic cloning starts with production of human embryos - Is it ethically acceptable to generate a new human embryo for the sole purpose of medical research? b. In nature, embryos are created only for reproduction and many people believe that using them for experiments is unnatural and wrong c. Embryonic stem cells has lead to major breakthroughs in human biology d. Scientists are coming closer and closer to growing skin to repair serious burns, growing new heart muscle to repair an ailing heart, growing new kidney tissue to rebuild a failing kidney e. With some exceptions, the majority of researchers are against the idea of reproductive cloning in humans