Genetic Engineering and Biotechnology

1. Genetic Engineering and Biotechnology IB topics 4.4.1-4.4.5 PCR and Introduction to DNA Profiling

2. What is genetic engineering • Genes from one organism are transferred to the genome of another • Also known as recombinant DNA • This can happen because remember, the genetic code is universal • Triplet code  amino acid • Important applications • Biotechnology • Pharmaceuticals, medicine, agriculture, forensics

3. The steps of genetic engineering • 1. Isolating the gene from the source gene • 2. Cutting up of DNA • 3. Isolating DNA • 4. Vectors for cloning • 5. Using plasmids as vectors

4. Isolating the gene from the gene source • DNA is divided into genes (units of inheritance) • Average of 2200 genes/chromosome • vary in length, but typically thousands of bases long • Each gene codes for a particular protein • For genetic engineering, genes need to be isolated and identified.

5. Isolating continued • DNA may be extracted from tissue by: • Mechanically breaking up the cells • Filtering off the debris • Breaking down the cell membranes by treatment with detergent • The protein framework is removed by incubation with a protein digesting enzyme (protease) • DNA can be isolated using ethanol

6. Cutting up of DNA • Genetic engineering began with the discovery of restriction enzymes • Occur naturally in bacteria • They protect against the activity of viruses by cutting up viral DNA • Many different restriction enzymes have been discovered and purified to use today • They cut at particular base sequences

7. Isolating DNA fragments • Electorphoresis • Process used to separate particles • DNA, RNA, proteins, and amino acids • Done in agarous gel (sugar) • Contain tiny pores (acts like a sieve) • Small particles move quicker than larger ones • Also use an electric field • The molecules separated also carry an electrical charge (P in DNA is negative)

8. Electrophoresis Animation • http://www.dnalc.org/ddnalc/resources/electrophoresis.html

9. Vectors for cloning • Vector: an agent that transports between one organism and another • Vectors are commonly found in bacteria • Plasmids (type of DNA) • Easily isolated and easily re-introduced • Plasmids replicate independently of the chromosome, so any gene added to the plasmid is replicated many times

10. Plasmids as vectors • Restriction enzyme cuts open the plasmid • The same restriction enzyme cuts out the gene • Segments are sealed back up using the enzyme ligase

11. DNA Profiling • Exploits techniques of genetic engineering to identify a person or organism from a sample of their DNA • Forensic science • Crime scenes • Fingerprints, fluids, hair, skin • Paternity cases

12. Homework • Due Monday, April 19 • Go to http://www.dnai.org/d/index.html • Click on human identification • Take notes on all four applications: • Profiling • Family • Murder • Innocence