Genetics 3.5 Genetic modification and biotechnology

Electrophoresis Gel electrophoresis is used to separate proteins or fragments of DNA according to size. DNA is negatively charged. Proteins can be neg or pos charged. Eukaryotic DNA must be broken into smaller fragments. Exposed to electric field. Gel resists movement ▫Smaller DNA segments move further.

DNA amplification by PCR PCR can be used to amplify small amounts of DNA Many copies made in a short period of time Copy specific DNA sequences not the whole genome ▫Selected by using a primer that binds to the start of a desired sequence Only a small amount needed to start. ▫Why would this be important?  Forensics  Fossils Data-based question p 188

DNA profiling DNA profiling involves comparison DNA Sequences that are known to vary considerably between individuals are selected and copied. ▫Why? Copied DNA is cut into fragments with restriction endonucleases (enzymes). Fragments separated using gel electrophoresis Pattern of bands = DNA profile Who dunnit? See Example: page 190 Who is the Daddy?

Genetic Modification Genetic modification = The transfer of genes from one species to another ▫Possible because the genetic code is universal  Same amino acid sequence translated  Same proteins produced Examples: ▫Producing human insulin using bacteria (see 2.7) ▫Introducing new characteristics to animal species: goats with spider silk protein in milk. ▫New varieties of crop plants (GM): tomatoes that are purple.

Genetic engineering Genetic engineering = the collective term for the techniques used to transfer genes from one species to another. Gene tranfer to bacteria with plasmids using restriction endonucleases and DNA ligase.

Genetic engineering Usually easier to obtain mRNA transcripts of genes Reverse transcriptase is an enzyme that can make DNA (called cDNA) from RNA

Assessing the risks of genetic modification Almost everything we do carries risk. Scientists must assess the risk associated with their research before carrying it out. ▫What is the chance of an accident or other harmful consequences? ▫How harmful would the consequences be? Discuss See p 194 and Data-based question p 195

Clones Clones: groups of genetically identical organisms, derived from a single original parent cell. Natural MethodsHuman involvment Asexual reproduction Garlic bulbs Strawberry plantlets Hydra budding Aphids Twins Plant cuttings Splitting embryos Transplanted nuclei

Dolly Activity: e%20Come%20A%20Long%20Way%20Dolly.pdfhttp://teach.genetics.utah.edu/content/tech/cloning/Youv e%20Come%20A%20Long%20Way%20Dolly.pdf Video: See p 199

Cloning simulation clickandclone/ clickandclone/