2 Changing the Living World 1. Selective Breeding: Selective breeding allowing only the organisms with desired traits to breedTakes advantage of naturally occurring variationEx: domestic dogs, cats, farm animals, most crops
3 Cont. Selective Breeding Hybridization crossing dissimilar individuals & bringing together the best of both organismsHybrids usually hardier than either of the parentsEx: crossing disease resistance with food productionInbreeding continued breeding of individuals with similar characteristicsIncreased risk of genetic defectsEx: maintaining characteristics in breeds of dogs
4 Ever wondered what a human-dog hybrid would look like?!?!
5 Human-Dog hybrid was a sculpture created by an Australian artist named Patricia Piccinini.
6 Increasing VariationBreeders increase variation by inducing mutations (*** ultimate source of variation) New kinds of bacteria produced by treating them with chemicals and radiation- Results: bacteria that can digest oil used to clean up oil spills
7 Cont. Increasing Variation New kinds of plants produced by treating them with drugs that prevent chromosome separation during meiosis- Results: polyploidy cells plants larger and stronger (LETHAL in animals!)
8 Manipulating DNAGenetic engineering making changes in the DNA code of an organism1. The Tools of Molecular Biologya. DNA extraction open cells and separate DNA from other cell partsb. Cutting DNA via restriction enzymes cut DNA into smaller pieces at a specific sequence of nucleotidesc. Separating DNA via gel electrophoresis mixture of DNA fragments are put in one end of porous gel and an electric voltage is applied- DNA is negatively charged so the fragments begin to travel toward the positive end of the gel- The smaller the fragment, the faster it travels; the larger/slower
9 Cutting DNARecombinant DNA is DNA taken from two different sources and fused into a single DNA molecule. Special DNA cutting enzymes, called restriction enzymes, cut the DNA at specific sites. Each restriction enzyme recognizes a different nucleotide sequence. DNA that is cut with a restriction enzyme will have single-stranded ends, called “sticky ends”. Two molecules of DNA cut with the same restriction enzyme will have the same exposed nucleotides and will undergo complementary base pairing.
12 Cont. Manipulating DNA 2. Using the DNA Sequence a. Reading the sequence use fluorescent dyes to identify specific bases and DNA sequencesb. Cutting and pasting via recombinant DNA use restriction enzymes to “cut” a gene form one organism and using special enzymes (ligase) “paste” it into the DNA of another organismc. Making copies via polymerase chain reaction (PCR) produces multiple copies of DNA strand
13 Cell Transformation1. Transformation process in which bacteria or some other organism takes in DNA from its environment and incorporates it into its own DNA a. Transforming BacteriaPlasmids small circular pieces of DNA useful for DNA transfer for 2 reasons:1. Bacterial origin of replication2. Genetic marker a gene that makes it possible to identify the transformed bacteriaEx: genes for resistance to antibiotics
15 Cont. Transformation b. Transforming Plant Cells Infect plant cells with recombinant plasmid whose tumor producing gene has been inactivatedc. Transforming Animal CellsInject DNA directing into the nucleus of an egg cell, foreign DNA is inserted into the chromosome
16 Applications of Genetic Engineering 1. Transgenic Organisms contain genes from other organismsa. Transgenic MicroorganismsBacteria transformed with human genes for insulin, growth hormone, clotting favors etc. produce human productsb. Transgenic AnimalsMice with human immune systems are used to study effects of diseaseLivestock with extra copies of growth hormone to produce faster growth and less fatty meatc. Transgenic PlantsGenetically modified food (GM) 52% of soy beans and 25% cornPlants contain genes that produce natural insecticide or weed resistance
18 Cloning1. Clone member of a population of genetically identical cells produced from a single cell Steps:1. Nucleus of egg cell removed2. Donor nucleus fused with egg cell using an electric shock3. Fused cell begins to divide4. Embryo placed in uterus of foster mother