Advances in Genetics

1. Advances in Genetics

2. Methods of Developing Organisms With Desirable Traits • Selective Breeding • Cloning • Genetic Engineering

3. Selective Breeding • The process of selecting a few organisms with desirable traits to serve as parents of the next generation. • Used for thousands of years with various plants and animals. • Types • Inbreeding • Hybridization

4. Inbreeding • Two individuals that have identical or similar sets of alleles are crossed. • Resulting organisms are very similar to their parents. • Used to produce breeds of animals with specific traits • Ex. Purebred Lab retrievers, German shepherds • Increases probability that organisms may inherit alleles that lead to genetic disorders. • Ex. Hip problems in many breeds of dogs

5. Hybridization • Two genetically different individuals are crossed • Organism is bred to have the best traits from both parents • Ex. Corn with many kernels crossed with disease-resistant corn • Most crops grown on farms and in gardens are hybrids.

6. Cloning • Although selective breeding does not allow the breeder to control whether the desired allele will be passed or not, cloning does. • Clone • Organism that is genetically identical to the organism from which it was produced. • Cloning Plants • Small part is cut from plant and regrows into a genetically identical plant.

7. Cloning in Plants

8. Cloning Animals • Dolly the Sheep • Removed egg cell from one sheep • Nucleus in egg cell replaced with nucleus from a six-year old sheep • Egg implanted into uterus of 3rd sheep • Dolly born 5 months later, genetically identical to the six-year old sheep

9. Genetic Engineering • Genes from one organism are transferred into the DNA of another organism. • Called “Gene Splicing” • DNA molecule cut open • Gene from another organism is spliced into it • Used to • Produce medicine • Improve food crops • Try to cure human genetic disorders

10. Genetic Engineering in Bacteria • Bacteria used because they reproduce rapidly. • Insulin gene spliced into bacteria- (into the plasmid)- so that the bacteria will produce insulin.

11. Genetic Engineering in Bacteria

12. Genetic Engineering in Other Organisms • Used in plants and other animals. • Ex. Human clotting gene inserted into cows. Cows then produce clotting protein in milk, which can then be extracted for humans. Gene Therapy • Working copies of a gene inserted directly into cells of a person with a genetic disorder • Used to correct some genetic disorders

13. Genetic Engineering

14. DNA Fingerprinting • DNA pattern is unique for each individual • Used often in crime investigations

15. Human Genome Project • Identified the DNA sequence of every gene in the human genome. • Involves nearly 25,000 genes • May lead to new treatments and prevention strategies for many genetic disorders and for diseases such as cancer.

16. Summary Questions • Name three techniques that people have used to produce organisms with desired traits. • Why do scientists want to identify the DNA sequence of every human gene? • What is genetic engineering? Describe three possible benefits of this technique. • Explain how a DNA fingerprint is produced. What information can a DNA fingerprint reveal?