Slide 1Slide 2Slide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14Slide 15Slide 16Slide 17Slide 18Slide 19Slide 20Slide 21Slide 22Slide 23Slide 24Slide 25Slide 26Slide 27Slide 28Slide 29Slide 30Slide 31Slide 32Slide 33Click to edit Master subtitle style 1/12/13 Chapter 5Raw material: heritable variation among individuals1/12/13 Proteins are chains of amino acids1/12/13 DNA codes for proteinMutation: any change to the genomic sequence1/12/13 Eukaryotic DNA is organized into chromosomes1/12/13 Chromosomes come in homologous pairs1/12/13 Ploidy can varyPloidy: Number of copies of unique chromosomes in a cell1/12/13 Production of protein from DNA requires transcription and translationGene expression: process by which information from a gene is transformed into product1/12/13 Ribosomes translate mRNA into protein1/12/13 Gene expression can be regulated in a number of ways1/12/13 RNA splicing can create multiple proteins from a single gene1/12/13 Regulation of gene expression is flexible1/12/13 Non-coding regions make up most of the genome•Non-coding regions include:–RNA genes–Pseudogenes–Mobile gentic elements1/12/13 microRNA can affect phenotypes1/12/13 Variation in genome size and complexityMost variation in size due to differences in mobile genetic elements1/12/13 Key Concepts•Most proteins function in four ways:–Enzymes–Cell-cell signaling–Receptors–Structural elements•Mutations are the raw material for evolution•In diploid organisms, deleterious mutations may be masked by a functional gene copy1/12/13 Key Concepts•All cells use mRNA to carry genetic information–Some viruses use RNA instead of DNA for the genome•Non-coding RNA plays critical roles in gene regulation1/12/13 Types of mutation1/12/13 Different types of mutation can alter the phenotype1/12/13 Examples of point mutations1/12/13 Germ line mutations are heritable•Somatic mutations: affect cells in the body of an organism; not heritable•Germ-line mutations: affect gametes; heritable and relevant to evolution1/12/13 Key Concepts•Changes in coding sequences and gene expression are heritable•Gene expression changes can affect when, where, and how much a gene is expressed1/12/13 Recombination generates variation1/12/13 Independent assortment ensures novel combinations of alleles1/12/13 Key Concepts•Meiosis generates considerable genetic variation–Recombination –Independent assortment1/12/13 Linking genotype and phenotype•Genotype: the genetic make-up of an individual•Phenotype: an observable measurable characteristic of an organism1/12/13 Simple polymorphisms can produce differences in phenotype1/12/13 Sometimes a single genotype can produce multiple phenotypesPolyphenic trait: single genotype produces multiple phenotypes depending on environment1/12/13 Quantitative traits influenced by genes and the environmentFrancis Galton (1822-1911)Quantitative traits influenced by multiple genes; generate a normal distribution1/12/13 Human height has genetic component1/12/13 QTL analysis can help discover genes influencing quantitative traits1/12/13 Key Concepts•Polyphenisms often result from a developmental threshold mechanism•Continuously varying traits are called quantitative traits•Evolutionary biologists study variation in the expression of phenotypic traits–Caused by genetic and environmental factors1/12/13 Environmental influences on gene expression•Phenotypic plasticity: changes in phenotype produced by a single genotype in different environments–Tailors organism to environment1/12/13 Key Concept•Gene expression often influenced by signals from the environment–Allows match to environmental