Genetics: Mendelian Laws & Genetic Engineering PDF

1 GENETICS What is genetics? Genetics is the study of heredity -- the process in which a parent passes certain genes onto their children.” What does that mean? Children inherit their biological parents’ genes that express specific traits, such as some physical characteristics, natura...

1 GENETICS What is genetics? Genetics is the study of heredity -- the process in which a parent passes certain genes onto their children.” What does that mean? Children inherit their biological parents’ genes that express specific traits, such as some physical characteristics, natural talents, and genetic disorders. 2 Match the genetic terms to their corresponding parts of the illustration. o base pair o cell o chromosome o DNA (Deoxyribonucleic Acid) o genes o nucleus Illustration Source: Talking Glossary of Genetic Terms http://www.genome.gov/ glossary/ 3 Within 15 minutes, use online resources or reference books to: a. Look up the definitions of the given words. b. Rewrite the definitions in your own words and note them in your notebook. 1. genes 2. Genome 3. Chromosomes 4. DNA 5. locus 6. Allele 7. heredity 8. dominant 9. recessive 10.homozygous 11.heterozygous 12.genotype 13. phenotype 6 14.Mendelian Inheritance MENDELIAN INHERITANCE A trait may not be observable, but its gene can be passed to the next generation. ▪ Each person has 2 copies of every gene—one copy from mom and a second copy from dad. These copies may come in different variations, known as alleles, that express different traits. 7 Mendel's garden on the abbey grounds where experiments in pea genetics were done. Why peas? Flower structure pollination and fertilization the offspring of peas For example, two alleles in the gene for freckles are inherited from mom and dad: o allele from mom = has freckles F o allele from dad = no freckles f Child has the inherited gene pair of alleles, Ff (F allele from mom and f allele from dad). Child’s allele : Ff Child’s genotype: Ff Child’s phenotype: has freckles 16 Pedigree A chart of a family’s history in regard to a particular genetic trait Males are squares Females are circles Shading represents individuals expressing disorder Half shade represent a carrier Horizontal line between circle and square is a union Vertical line down represents children of that union Counselor may already know pattern of inheritance and then can predict chance that a child born to a couple would have the abnormal phenotype Have a look at the pedigree above? What does this tell you about the disease? Well the first and most obvious thing is that this disease is caused by a recessive allele, h. If you see two people who don’t have the disease producing one or more children who do, then this must be a genetic disease caused by a recessive allele. In the top generation, parents 1 and 2 do not have the disease, but they have three children 2,3,4 one of whom has the disease. What does this tell us about the genotype of parents 1 and 2 in generation I? Well if neither have the disease and they have a child who does, both 1 and 2 in the top generation must be heterozygous – Hh Anyone with the disease must be homozygous recessive hh. Have a look at generation II in the diagram above? The man, number 2, who is a sufferer and so genotype hh marries woman 1 who does not have the disease. They produce 4 children, three with the disease and one without. What must the genotype of the woman 1 be? Well she must be heterozygous Hh. How do we know? What children would she produce if she were a homozygous HH woman? A pedigree caused by a dominant allele would look very different. Every sufferer would have at least one parent who also suffers from the disease. Two sufferers producing some children who do not have the disease is indicative of a disease caused by a dominant allele. If we use the symbol P for the dominant allele that causes the disease, and p for the recessive allele that is “normal”, work out the genotypes of all 12 people on the diagram above. (5-10 minutes) Lec-8-DNA-Recombination.pdf GENETIC ENGINEERING WHAT IS THE DIFFERENCE BETWEEN THE MICE IN THESE TWO GROUPS? WHAT IS GENETIC ENGINEERING? Genetic engineering is the direct modification of an organism’s genome, which is the list of specific traits (genes) stored in the DNA. Changing the genome enables engineers to give desirable properties to different organisms. Organisms created by genetic engineering are called genetically modified organisms (GMOs).  HISTORY OF GMO DEVELOPMENT 1973: created first genetically modified bacteria 1974: created GM mice 1982: first commercial development of GMOs (insulin-producing bacteria) 1994: began to sell genetically modified food 2003: began to sell GMOs as pets (Glofish)  WHAT IS THE GMO PROCESS? ▪ All genetic changes affect the protein synthesis of the organism. ▪ By changing which proteins are produced, genetic engineers can affect the overall traits of the organism. ▪ Genetic modification can be completed by a number of different methods: ❑ Inserting new genetic material randomly or in targeted locations ❑ Direct replacement of genes (recombination) ❑ Removal of genes ❑ Mutation of existing genes  GMO BACTERIA Bacteria are the most common GMOs because their simple structure permits easy manipulation of their DNA. One of the most interesting uses for genetically modified bacteria is the production of hydrocarbons (plastics and fuels) usually only found in fossil fuels. ▪ Cyanobacteria have been modified to produce plastic (polyethylene) and fuel (butanol) as byproducts of photosynthesis ▪ E. Coli bacteria have been modified to produce diesel fuel  ENGINEERING PLANTS How might genetic engineering modify plants to solve everyday problems? (Consider world hunger, weather problems, insecticide pollution…)  GENETICALLY MODIFIED CROPS GMO crop production in the US (2010): ▪ 93% of soybeans ▪ 93% of cotton ▪ 86% of corn ▪ 95% of sugar beets Example: ▪ One common modified crop is Bt-corn. ▪ A gene from the Bt bacteria is added so the corn produces a protein that is poisonous to certain insects but not humans.  Banana Vaccines Modified virus injected in sapling tree causes the bananas to contain virus proteins Venomous Cabbage Scorpion genes added to the cabbage prevent insects from eating it OTHER REASONS TO GENETICALLY MODIFY CROPS ▪ Insect resistant ▪ Herbicide resistant ▪ Drought/freeze resistant ▪ Disease resistant ▪ Higher yield ▪ Faster growth ▪ Improved nutrition ▪ Longer shelf life  ENGINEERING ANIMALS Could genetic engineering be used to modify any animals to solve problems?  BIOLUMINESCENT ANIMALS Uses: ▪ Protein tracking ▪ Disease detection using bioluminescent imaging (BLI) to identify different types of cells ▪ Novelty pets (Glofish are available now)  Fast-Growing Salmon Genes from two other fish cause this salmon to continually produce growth hormones Less Smelly Cows Modifying bacteria responsible for methane production in cattle results in 25% less-flatulent cows  COULD SPIDERMAN BE REAL? Web-Producing Goats Spider genes in goats enable the production of spider silk in goat milk  GMO CONCERNS What are some concerns regarding genetically modified foods and animals? ▪ Risk to human health; unsafe to eat ▪ Harm to the environment and wildlife ▪ Increased pesticide and herbicide use ▪ Farmers’ health ▪ Seed and pollen drift ▪ Creation of herbicide-resistant super weeds ▪ What about genetic engineering in humans? Nearly 50 countries around the world, including Australia, Japan and all of the countries in the European Union, have enacted significant restrictions or full bans on the production and sale of genetically modified organism food products, and 64 countries now have GMO labeling requirements.