PowerPoint PresentationSlide 2Slide 3Slide 4A summary of eukaryotic transcription and translationSlide 6How Do Mutations in DNA Affect the Function of Genes?Mutations in DNASlide 9Categories and consequences of point mutations: Base-pair substitutionThe molecular basis of sickle-cell disease: a point mutationSlide 12Categories and consequences of point mutations: Base-pair insertion or deletionSlide 14Slide 15Slide 16Slide 17Slide 18Slide 19Slide 20Slide 21Slide 22Slide 23Slide 24Slide 25Slide 26Slide 27Slide 28Slide 29Slide 30Slide 31Slide 32Slide 33Slide 34Slide 35Slide 36Slide 37Slide 38Slide 39What Causes Evolution?Slide 41Slide 42Slide 43Slide 44Slide 45Slide 46Slide 47Slide 48Slide 49Slide 50Slide 51Slide 52Slide 53Slide 54Slide 55Slide 56Slide 57Slide 58Evolution is a change in the frequencies of different alleles in a species or population over the course of many generations.Human ChromosomesDNAmessenger RNAproteinTranscription(cytoplasm)(nucleus)geneTranslationA summary of eukaryotic transcription and translationtemplate DNA strandcomplementaryDNA strandDNAgenecodonsanticodonsamino acids etc. etc. etc. etc.mRNAtRNAprotein etc.How Do Mutations in DNA Affect the Function of Genes?Mutations Result from Nucleotide Substitutions, Insertions, or DeletionsMutations May Have a Variety of Effects on Protein Structure and FunctionMutations in DNA•Point Mutations in DNA may result in the following changes in Protein–Silent mutation: No change in protein.–Missense: Amino acid substitution.–Nonsense: Stop codon introduced in the middle.•Frameshift mutations in proteins are due to insertion or deletions in the DNA.There are several types of mutations:Point Mutations. Change 1 nucleotide for another.Example: THE DOG ATE THE RAT AND CATTHE DOG ATE THE BAT AND CATCategories and consequences of point mutations: Base-pair substitutionThe molecular basis of sickle-cell disease: a point mutationGlutamic Acid (hydrophilic)Valine (hydrophobic)Categories and consequences of point mutations: Base-pair insertion or deletionFrameshift Mutations.InsertionExample:THE DOG ATE THE BAT AND RAT…THE DOG AAT ETH EBA TAN DRA T….DeletionExample:THE DOG ATE THE BAT AND RAT…..THD OGA TET HEB ATA NDR AT……AIt might be a little counter-intuitive, but 3 frameshift changes can actually cause the sequence to revert back to normal.THE DOG ATE THE RAT AND CAT….1. THE DDO GAT ETH ERA TAN DCA T….2. THE DDO XGA TET HER ATA NDC AT….3. THE DDO XGN ATE THE RAT AND CAT….There are several types of “selection”1. Natural Selection: The unequal survival and reproduction of organisms due to environmental forces, resulting in the preservation of favorable adaptations. Usually, natural selection refers specifically to differential survival and reproduction on the basis of genetic differences among individuals.Note: “Environmental forces” can and does include other biological organisms, not just climate, temperature or geology.The differential survival and reproduction of organisms with genetic characteristics that enable them to better utilize environmental resources2. Artificial Selection: A selective breeding procedurein which only those individuals with particulartraits are chosen as breeders; used mainly to enhance desirable traits in domestic plants andanimals.Note: Artificial selection results in “domestication.”Researchers have identified corn genes that were preferentially selected by Native Americans during the course of the plant's domestication from its grassy relative, teosinte, (pronounced "tA-O-'sin-tE") to the single-stalked, large-eared plant we know today. The study revealed that of the 59,000 total genes in the corn genome, approximately 1,200 were preferentially targeted for selection during its domestication.3. Kin Selection: a type of natural selection that favorsa certain allele because it increases the survivalor reproductive success of relatives that bear thesame allele.Social Insect Colonies.Alarm CallsHelpers at the nest4. Sexual Selection: A form of natural selection thatdepends “not on the struggle for existence in relation to other organic beings or to externalconditions, but on a struggle between the individuals of one sex, generally the males, forthe possession of the other sex.” Darwin, 1871Note: Is sometimes abbreviated: “Male competition;female choice”Mutations Are the Source of Genetic VariabilityEvolutionary change in a population can occur in a variety of ways.Evolution by natural selection is another way that allele frequencies can change over generations.This can be seen by looking directly at the proportions of alleles in a population.The Gene Pool is thesum of the genesin a population.The Frequency of Alleles in a Population can be defined by the Hardy-Weinberg Equilibrium Equation:1 or 100% = p2 + 2(pq) + q21 or 100% = AA + Aa + aaIf these frequencies change from 1 generation to another, EVOLUTION HAS OCCURRED.The Hardy-Weinberg Equilibrium Population Is a Hypothetical Population That Does Not Evolvep2 + 2pq + q2 = 1 p + q = 1In order for the allele frequencies to stay the same, the following conditions must be met:No mutations.No gene flow between populations. No movement of alleles into or out of a population.The population must be very large.All matings must be random. No preferences.No natural selection. All genotypes must reproduce with equal success.This can NEVER happen!!So, 2 causes of evolutionary change in a population are: 1. MUTATION2. SELECTION (NATURAL OR OTHERWISE)Additional causes for gene frequencies to change would be:3. GENE FLOW4. GENETIC DRIFTWhat Causes Evolution?Gene Flow among populations can also change allele frequenciesGene FlowAllele Frequencies Can Change in Small Populations Just Due to Chance OccurrencesThis is called “GENETIC DRIFT”a. Population Bottleneck b. Founder effecttimeevent causingbottleneckresulting populationoriginal populationMost species have about 20-40% heterozygous lociBottleneck effect. From an original peccary population with its own gene pool, a few individuals squeeze though a "bottleneck". In this case a few peccaries with the genotype bb survive a catastrophe. These individuals become the founders (originators) of a new peccary population.As they reproduce, the new gene pool is very different from that of the original population.Seals were hunted into near extinction by the late 1890’s (one male yielded 25 gallons of oil); 20 individuals remained.Cheetahs only have about