ANT 102 1st Edition Lecture 5Outline of Last Lecture II. Review of previous lecture III.DNAIV. Sexual and Asexual reproductionV. Mendel’s Second PrincipleOutline of Current Lecture I. VocabularyII. Hardy-Weinberg ModelIII. Non-random matingIV. Founder effect and subsequent inbreedingCurrent LectureBreeding pop: group of organisms of the same species that readily reproduce with each otherGene pool: all available alleles present within a populationWe’re not looking for phenotype or genotype…simply looking at overall frequency of different alleles in a population and its gene poolEx: hair colorBlack Blonde Brown RedP generation 30% 30 30 10F1 generation 20 35 25 20(These changes in allele frequency indicates that evolution has occurred (microevolution))Hardy-Weinberg Model: Developed independently by Godfrey H Hardy and Wilhelm WeinbergThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Standard for measuring whether a population is evolvingPractice:Given a set of allele frequency,what is probability of getting different genotypes?Equation: P^2+2pq+q^2=1Dice example: what is the probability of rolling a 3 on the first try with a single die? 1/6Both come up with 3 when two dice are rolled? 1/36Consider a two allele system for height: tall (T), short (t)In a population with p=30% T and q=70%t, what is the probability of being homozygote tall?30% x 30%= 9% (p^2)Homozygote short: 70% x 70%=49% (2pq)Heterozygote: 2 x 30% x 70%=42% (q^2)If we know the allele frequencies, we can predict the genotypesUnder what conditions will the Hardy-Weinberg Model predict genotype frequencies?Must meet the follow conditions:1. Mating is random2. Mutation is not occurring*3. No migration in/out of pop*4. Natural selection is not acting on trait*5. Pop is infinitely largeIf these are met, H-W Equilibrium *Numbers 2-4 negate forces of evolutionHardy-Weinberg Modelequilibrium: Will have genotype frequencies described by that equationAllele frequencies will not change over time (population is not evolving)Gives an “ideal”, control to compare to natural populationsAllows us to predict future genotype frequencies in a non-evolving scenarioNon-random mating:Positive assortative: mating with similar phenotypes (with respect to trait)This leads to more homozygote organismsNegative assortative: mating with dissimilar phenotypeLeads to more heterozygote organismsInbreeding: production of offspring by mating individuals that are closely relatedLeads to more widely expressed defective alleles more quickly (reduces reproductive success and leads to the population dying out)Can be useful in artificial selection (you can propagate positive alleles as easily as negative)Can actually breed out deleterious alleles from the population, as long as the population can rebound from the initial reproductive pauseOnly one species has ever escaped the inbreeding trough….naked mole ratCulturally mediated founder effect and subsequent inbreeding:Ellis-van Creveld SyndromeInherited as an autosomal recessive mutations in one of two genesOld Order AmishPracticed strict within community mating resulting in only one gene poolHapsburg lip/jawSpaniards with jutted out chinKing Charles II of Spain (mentally insane due to such long lines of inbreeding)Why might deleterious alleles persist in a population?Deleterious: bad, opposite of positive, negative effect, disastrousBalanced polymorphism: maintenance of multiple alleles by selection of heterozygotesEx: Sickle cell anemia, Tay Sachs disease People with heterozygote genotypes of diseases like those listed above are resistant to other diseases, such as tuberculosis Malaria is an endemic disease and always presentUnlike an epidemic—which comes and goes—it’s not a question of IF you get it, but WHENMost of the resistant genes we have to fight these diseases are a result of advancing