Biology 171 1st Edition Lecture 10 Outline of Last Lecture I. Types of Selection Cont. II. Sexual Selection III. Genetic Drift/Gene Flow Outline of Current Lecture I. Population GeneticsII. InbreedingIII. Hardy-Weinberg Equilibrium Current LecturePopulation Genetics -The effects of non-adaptive evolutionary processes on genetic variationoGene flow (resulting from migration) can either increase or decrease genetic variation oGenetic drift will decrease genetic variation because when certain genes "drift" out of the population, they become lost, and that trait will no longer be found in thatinitial population oMutations will increase genetic variation because they introduce new alleles into the population, generating new variation-The Modern SynthesisoCombines Mendelian genetics with Darwin and Wallace's ideasoDefines biological evolution as a change in allele frequencies in a population overone or more generations -Population genetics is the study of the genetic variation within and among natural populations, and the evolutionary processes that generate and maintain this variation. oPopulation vs. gene pool These 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.-Population= a group of individuals of the same species living in the same area that are capable of interbreeding Populations evolve NOT individuals -Gene pool= all the alleles (for all genes) in the population -The two sources for genetic variation are mutations and recombination oMutations create new alleles within populations -Can be somatic mutations or germ-line mutations, but only germ-line will be passed on to offspring because they are mutations in the sex cells oRecombination makes recombinant genotypes from non-sister chromatids sharing or exchanging parts of their DNA sequences -Genetic makeup of a population can be measured using the allele frequency or the genotype frequency oAllele frequency= (# of copies of a given allele)/(total # of alleles of the gene that you are studying)-Ex) percentage of individuals who posses the Dominant allele (can come from homo. Dominant or hetero.)-Can calculate frequency of dominant allele using formula: (AA+ Aa/2)/# of individuals -Can calculate frequency of recessive allele using formula: (aa+ Aa/2)/ # ofindividuals -Allele frequency is how we keep track of evolution oGenotype frequency= (# of individuals of a given phenotype)/(total # of individuals) -Ex) percentage of individuals that are homozygous dominant Inbreeding -Inbreeding= mating between close relatives (or self-fertilization) -It is NOT an evolutionary process, but it does change genotype frequencies oOver several generations it will increase the proportion of homozygous offspringoIt does NOT change allele frequenciesHardy-Weinberg Equilibrium -The HWE states that after one generation of random mating, genotype frequencies for two alleles at one gene will be p^2, 2pq, and q^2.oWhere p= frequency of dominant allele and q=frequency of recessive allele (p + q= 1)-p^2= homozygous dominant -2pq= heterozygote-q^2= homozygous recessive -Allele and genotype frequencies will remain constant in succeeding generations as long as the conditions are met: oPopulation size is VERY large (no genetic drift affecting the gene being studied) oPopulation is closed (no migration or gene flow occurring)oNo mutations are occurring at the gene being studied oMating is random with respect to the trait being studied (meaning no sexual selection or inbreeding)oAll genotypes in the population have equal chance of surviving and reproducing (meaning no natural selection)-If a gene within a population is in HWE, then that gene is not