exam1_notes - Chapter 1Genetics and the Organism (8-31-05)...

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1 Chapter 1 Genetics and the Organism (8-31-05) Genetics Study of gene function, from molecules of DNA to the gene pool of a population. DNA contains ALL of the information for building an organism. Central Dogma of Molecular Biology (Information Flow) DNA RNA Protein Genes Functional units of DNA. Individuals inherit genes. Individuals contribute to the gene pool of a population. Alleles Different, but related, forms of the same gene. Genotype The set of genes an organism inherits. (Very little change over time) Phenotype Characteristics of an organism. Phenotypes change throughout the life of an organism as its genes interact with the environment. Phenotype is determined by the genotype as it interacts with the environment. Interactions between genes and the environment determine what organisms become. Geneticists study partial genotypes and partial phenotypes of organisms. (i.e. study the effect of one or a few genes) A particular phenotype can be caused by more than one genotype. A/A dominant phenotype A/a dominant phenotype a/a recessive phenotype Wild Type (WT) genotypic or phenotypic characteristics of natural populations or standard laboratory strains. An individual that is not WT is a variant or mutant . Mutation is the basis for variation within a species and is the raw material for evolution.
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2 Model Organisms Genetic analysis is greatly simplified by using an easily followed phenotype in an organism that is practical to study. (e.g. mice vs. elephants) 1. Bacteriophage and viruses 2. Bacteria ( E. coli and B. subtilis ) 3. Yeast (Bread and Beer!!) 4. Caenorhabditis elegans (round worm) 5. Drosophila melanogaster (fruit fly) 6. Maize (corn) 7. Arabidopsis thaliana (small plant) 8. Mus musculus (mice) Developmental Noise Random molecular events in cells of a developing organism that cause phenotypic variations. Thus, the genotype determines the phenotype; however, expression of the information in the genotype is influenced by the environment, developmental noise, and other genes. For Genetic Analysis 1. A phenotype that is easy to identify and monitor. 2. A phenotype that is not highly influenced by the environment (control the environment). 3. Try to determine the influence of a single gene. Genetic Dissection —Identify a process to study —Isolate mutants that interfere with the process —Identify (clone) the WT genes —Determine the function of the gene products
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3 Chapter 2 Patterns of Inheritance (9-2-05) Mendelian Analysis Analyzing hereditary information using Mendel’s techniques and principles. Gregor Mendel (1860s) Conducted quantitative and systematic studies of inheritance. Proposed the concept of the gene. Particulate Inheritance
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This note was uploaded on 07/23/2008 for the course BIOL 222 taught by Professor Babitzke,paullee during the Fall '07 term at Pennsylvania State University, University Park.

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exam1_notes - Chapter 1Genetics and the Organism (8-31-05)...

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