Advances in Genetics Lesson 5 May 16 6:43 PM How can organisms be produced with desired traits? May 16 6:44 PM 1
I. How can organisms be produced with desired traits A. With advance in genetics, DNA evidence can show many things like family relationships and the ability to produce organisms with desired traits Selective breeding, cloning, and genetic engineering are three different methods for developing organisms with desired traits May 16 6:45 PM B. Selective breeding The process of selecting organisms with desired traits to be parents of the next generation People have used selective breeding with many types of plants and animals ex. corn started over a thousand years ago in present day Mexico. Farmers plant seeds from the best plants that yielded the most food. May 16 6:50 PM 2
Two techniques for selective breeding are inbreeding and hybridization * Inbreeding involves crossing two individuals that have similar desirable characteristics produces organisms that are genetically very similar when inbred organisms are mated, the chances of inheriting two recessive alleles increases. This can lead to genetic disorders ( hip problems in golden retrievers) May 16 6:53 PM * Hybridization breeders cross two genetically different individuals hybrid has two different alleles for a trait hybrid organism that is the result is bred to have the best traits from both parents ex. farmer might cross a corn plant that produces many kernels with a disease resistant plant roses and other types of flowers are also commonly crossed May 16 6:59 PM 3
Gardeners and plant breeders use hybridization to develop roses with certain characteristics. What will the hybrid offspring look like? May 16 7:03 PM Changing Rice Production This data table shows how worldwide rice production changed between 1965 and 2005. Plot the data from the table and determine a line graph. May 16 7:04 PM 4
C. Cloning A clone is an organism that has exactly the same genes as the organism from which it was produced * Some kinds of plants are easy to clone ex. African Violet cut the stem from one plant and place in soil. Water. New plant produced is genetically identical to the stem plant May 16 7:04 PM D. Genetic Engineering Genes from one organism are transferred into the DNA of another organism * genetic engineering can produce medicines and improve food crops May 16 7:12 PM 5
* Genetic Engineering in bacteria One type of bacterium is genetically engineered to produce a human protein called insulin many people with diabetes need insulin injections Bacteria has a single DNA molecule in the cytoplasm and smaller DNA pieces called plasmids. Scientists insert the gene for insulin into the plasmid. Bacteria will produce the human code for insulin May 16 7:34 PM * Genetic engineering in other organisms Scientists can also use genetic engineering techniques to insert genes into animals ex. Human genes inserted into cows to produce a protein needed by people with hemophilia. Protein helps their blood to clot ex. Genes inserted into tomatoes and rice to help them withstand the cold temperatures, poor soil or resist insects May 16 7:38 PM 6
* Gene therapy Someday it may be possible to use genetic engineering to correct some genetic disorders in humans. This process will involve inserting copies of genes directly into a person's cells ex. Treating hemophilia by replacing the defective allele on the X chromosome May 16 7:42 PM * Concerns about genetic engineering Some people are concerned about the long term effects of genetic engineering * may not be entirely safe * may harm the environment * may cause health problems in humans scientists are studying the effects of genetic engineering May 16 7:44 PM 7