Transcript PPT File
CHAPT. 12 I. MODIFYING THE LIVING WORLD • A. BREEDING STRATEGIES • 1. SELECTIVE BREEDING, breed for desired traits. – INBREEDING is often used to do this, but this can cause UNDESIRABLE TRAITS to appear (reduced genetic variety in the gene pool of the population) • 2. HYBRIDIZING, breeding between similar organisms or two different species (birds/plants) • MULE- hybrid between a horse (Genus/species Equus caballus) and a donkey (Genus/species Equus asinus) • Created for strength and agility • Sometimes this technique is used for endangered species. The English Bulldog Then Now The Good, the Bad & the Healthy Test Cross When you don’t know the genotype of a breed • If you have an organism that expresses a dominant trait do you know for sure if it is a purebred? • NO! • So you could breed it with a ___________ trait animal and look at the offspring to know. Example of a test cross B. MUTATIONS Worksheet • Can cause new characteristics to appear because a gene is turned on or off – so either a protein is made or not made which controls a function of the body – this can be beneficial, harmful or neither • MUTAGENS- anything that can cause mutations • Examples • Radiation X-rays, atomic bomb, • Toxic chemicals in food, water air • U.V. radiation Using Technology to alter our world HUMAN GENOME PROJECT • Started in 1990, completed in 2003 • Sequenced all 25,000 HUMAN GENES on all 23 chromosomes • Scientists now are studying INDIVIDUAL GENES on chromosomes for disease links, mutations Gene Therapy Procedure Gene Therapy Worksheet • Potential to use Gene therapy as a cure. See the worksheet in your packet. • Let’s see how this works. • Example-Parkinson’s disease. Condition that affects brain cells. Causes tremors and uncontrolled movement. DNA STUDIES Did you solve the crime? • • • • • DNA FINGERPRINTING Who was the lollypop thief? Honey! Now, let’s do the worksheet Identify individuals their DNA patternspaternity case Use a Gel Electrophoresis – Crime solving- DNA from victim and criminal – Anthropology- DNA from Neanderthals – Can also detect mutations Gel Electrophoresis equipment Gel Electrophoresis of human DNA Look at the bands and find the ones that match the victims blood. GENETIC ENGINEERING Homework-animations online and worksheet handout using bacteria to create transgenic plants THE USE OF BIOCHEMICALS TO INDENTIFY, STUDY OR MODIFY GENES IN ORGANISMS Recombinant Plasmid in bacteria click the link Recombinant Plasmid in plants click the link Making Recombinant DNA from Bacteria Let’s review your worksheet • Bacteria are PROKARYOTES, they have no nucleus • Their DNA is inside a PLASMID-small, circular sequence of DNA inside the cytoplasm and also have chromosomes Genetic Engineering Technique • 1. Genes are cut at specific nitrogen base sequences in the plasmid by enzymes called, RESTRICTION ENZYMES • Each type of enzyme can cut only a specific DNA sequence TECHNIQUE • 2. Then a gene from a different organism is cut , removed & inserted into the space left in the plasmid. – Example Insulin (controls blood sugar) gene from a pig • 3. The gene is “glued in place using____________, an enzyme. – Combining DNA from Genes of different organisms is called, RECOMBINANT DNA • 4. Scientists then use a VECTOR, an organism that will carry the recombinant DNA • The VECTOR is usually a bacterium or virus TECHNIQUE • The vector is now referred to as a TRANSGENIC organism. They have foreign genes in their genome. • 5. The vector is allowed to reproduce. When it does the daughter cells have the recombinant DNA. • Bacteria can produce billions of cells in 24 hours – So you can produce lots of a gene in very little time. USES FOR GENETIC ENGINEERING • Genetic Engineering • MANUFACTURE DRUGS – Example production of insulin for diabetic patients. – Antibiotics for bacterial infections • Gene Therapy- Inactivate a defective gene or insert a missing genes into sick patients using a non-lethal virus as the vector Uses for Genetic Technology Cloning How they made a cloned sheep Therapeutic Cloning click the link