1. Chapter 13 Genetics and Biotechnology

2. Applied Genetics

3. Selective Breeding The process by which desired traits of certain plants and animals are selected and passed on to their future generations is called selective breeding Saint Bernard Rescue dog Husky Sled dog German shepherd Service dog

4. Hybridization Hybrid organisms can be bred to be more disease-resistant, to produce more offspring, or to grow faster. Organisms are bred to have a competitive edge Cross must be done carefully to get the right combination of traits from the parents A disadvantage of hybridization is that it is time consuming and expensive. It took 30 years to create a hybrid rice variety with a higher yield than the nonhybrid

5. Inbreeding The process in which two closely related organisms are bred to have the desired traits and to eliminate the undesired ones in future generations A disadvantage of inbreeding is that harmful recessive traits also can be passed on to future generations. Pure breeds are maintained by inbreeding (german shepard, Boston Terrier)

6. Test Cross A test cross involves breeding an organism that has the unknown genotype with one that is homozygous recessive for the desired trait If a breeder wants only white grapefruit but has mixed varieties in the field, they would cross red(ww) with the whites(Ww and WW) to figure out how to get an all white(WW) orchard

7. DNA Technology Genetic Engineering Technology that involves manipulating the DNA of one organism in order to insert exogenous DNA (the DNA of another organism) Genetically engineered bollworm Scientists have inserted GFP (a green fluorescent protein) – this protein is which glows in ultraviolet light is found naturally in some jellyfish in the north Pacific Ocean

8. Genetic Engineering Genetically engineered organisms are used to study the expression of a particular gene to investigate cellular processes to study the development of a certain disease to select traits that might be beneficial to humans.

9. DNA An organism’s genome is the total DNA in the nucleus of each cell Scientists use DNA tools to manipulate DNA and to isolate genes from the rest of the genome.

10. DNA TOOLS Restriction enzymes recognize and bind to specific DNA sequences and cleave the DNA within the sequence Scientists use restriction enzymes as powerful tools for isolating specific genes or regions of the genome.

11. DNA TOOLS EcoRI is a restriction enzyme EcoRI specifically cuts DNA that contains the sequence GAATTC. The cut ends of the 2 fragments are called sticky ends

12. DNA TOOLS The sticky ends of the DNA fragments can bind to another DNA fragment that is complementary to the original fragment Some resriction enzymes create blunt ends not sticky ends – blunt ends bind with other blunt ends

13. DNA TOOLS Gel Electrophoresis An electric current is used to separate DNA fragments according to the size of the fragments When an electric current is applied, the DNA fragments move toward the positive end of the gel The smaller fragments move farther faster than the larger ones

14. DNA TOOLS The unique pattern created based on the size of the DNA fragment can be compared to known DNA fragments for identification. Gel electrophoresis

15. Southern Blot Gel Electrophoresis is used to separate the DNA fragments Next a Southern Blot is prepared Southern Blotting Technique - transfer of DNA from the gel to filter paper. A Southern Blot can be kept and is easier to manipulate and analyze than the gel

16. Southern Blot A southern blot can also be treated with radioactive isotopes to isolate certain sequences for better analysis

17. Recombinant DNA A newly generated DNA molecule with DNA from different sources

18. Recombinant DNA Scientists need large quantities of recombinant DNA in order to study it In order to make these, scientists use vectors (usually viruses) to carry the DNA fragments into bacterial cells DNA Ligase is used to join the bacteria plasmid and the DNA fragment This new recombinant DNA can then be inserted into a host cell to be replicated

19. Gene Cloning Large numbers of identical bacteria, each containing the inserted DNA molecules, can be produced through a process called cloning Bacterial transformation causes some bacterial cells to take the plasmid into the cell

20. DNA Sequencing To understand how DNA is sequenced, scientists mix an unknown DNA fragment, DNA polymerase, and the four nucleotides—A, C, G, T in a tube Each nucleotide is tagged with a different color of fluorescent dye Every time a modified fluorescent-tagged nucleotide is incorporated into the newly synthesized strand, the reaction stops The sequencing reaction is complete when the tagged DNA fragments are separated by gel electrophoresis

21. DNA Sequencing Scientists then use a DNA sequencing machine to detect the color of each tagged nucleotide The original DNA sequence can then be determined from the order of the tagged fragments

22. Polymerase Chain Reaction Used to make millions of copies of a specific region of a DNA fragment DNA is heated and separated. New nucleotide are brought in to pair with the DNA Used in forensics and medicine

23. Biotechnology Use of genetic engineering to find solutions to problems Transgenic organisms – contain a gene from another organism

24. Transgenic organisms Transgenic animals – used in laboratories to study diseases Transgenic goats secrete a protein used during surgery that keep human blood from clotting Transgenic plants – engineered to be more resistant to insects and viruses Working on peanuts and soybeans that do not cause allergic reactions in humans Transgenic bacteria Insulin, substances that dissolve blood clots, oil spill clean up and garbage decomposition

25. Human Genome Project International Project completed in 2003 Genomics – study of organism's genomes Researchers determined the sequences of the 3 billion nucleotides and identified 20,000 -25,000 human genes It was similar to decoding a book written in code Researchers used restriction enzymes to cleave the DNA and used recombinant DNA technology then cloned the bacteria and used machines to aid in the sequencing

26. DNA Fingerprinting Developed in England in 1985 Scientists use gel electrophoresis and southern blotting to analyze specimens from an organism The distinct banding pattern produced by the DNA in the specimen can then be compared to the pattern of individuals. Used in forensics, to determine paternity and to identify soldiers killed in war

27. Identifying genes Now that scientists have mapped the human genome they are working on identifying the function of the 20,000 human genes Scientists look for start and stop codons in the sequences and then look in between these codes. Scientists have been able to identify 90% of the genes in yeast and bacteria but humans are much more complex

28. Bioinformatics New field of science – creates, and maintains databases of biological information These scientists then analyze the information To find genes on the DNA Predict structure and function of new proteins Study the evolution of genes

29. DNA Microarrays Tiny microscope slides or silicon chips that are spotted with DNA fragments Uses to help determine whether expression of certain genes is genetic or environmental Scientist can compare different cell DNA for differences in the gene expression (normal vs. cancer cells) DNA is isolated and place onto a slide then analyzed by a computer

30. Microarray

31. HapMap Project Haplotypes – regions of linked genes in the DNA Scientists creating a catalog of common genetic variations, where they are on the DNA and how they are distributed in populations Will allow scientists to find genes that cause disease and can affect individual responses to a drug

32. Gene Therapy Inserting a normal gene to replace a dysfunctional gene Scientists use recombinant DNA with the correctly functioning gene The recombinant DNA is inserted into a virus Cells are targeted in the organism to infect with the virus The recombinant DNA is inserted into the organisms cell and the gene begins to function