《医学遗传学 Medical Genetics》课程PPT教学课件（英文版）Population Genetics

Medica, Genetics Population Genetics

Population Genetics Medical Genetics

Population genetics investigates genetic structure and genetic variation among individuals within groups Mendelian population is a group of interbreeding individuals, who live in the same place and share a common set of genes(gene pool

Population genetics investigates genetic structure and genetic variation among individuals within groups. Mendelian population is a group of interbreeding individuals, who live in the same place and share a common set of genes (gene pool)

Gene Frequency & Genotypic Frequency Allelic frequency: a proportion or a percent of allele. Genotypic frequency: the number of individuals with one particular genotype divided by the total number of individuals in the population

Allelic frequency: a proportion or a percent of allele. Genotypic frequency: the number of individuals with one particular genotype divided by the total number of individuals in the population. Gene Frequency & Genotypic Frequency

Gene Frequency & Genotypic Frequency ●●● N● ●●● Genotype: MM 5, MN7; NN 4 Allelic frequency of M: P=(2X5+7/(2X16)=0.5312 Allelic frequency of N: q =(2X4+7/2X16)=0.4688

Gene Frequency & Genotypic Frequency M N Genotype: MM 5; MN 7; NN 4 Allelic frequency of M：p ＝(2×5＋7)/(2×16)＝0.5312 Allelic frequency of N：q ＝(2×4＋7)/(2×16)＝0.4688

Law of Genetic Equilibrium Hardy-Weinberg law Hardy gh Weinberg w

Law of Genetic Equilibrium Hardy-Weinberg law Hardy GH Weinberg W

Law of Genetic Equilibrium Hardy-Weinberg law Explains how Mendelian segregation influences allelic and genotypic frequencies In a population

Explains how Mendelian segregation influences allelic and genotypic frequencies in a population. Law of Genetic Equilibrium Hardy-Weinberg law

Law of Genetic Equilibrium Hardy-Weinberg law Assumptions %o Large population 令 Random mating ☆ No natural selection No mutation 今 No migration If assumptions are met, population will be in genetic equilibrium

Law of Genetic Equilibrium Assumptions ❖ Large population ❖ Random mating ❖ No natural selection ❖ No mutation ❖ No migration If assumptions are met, population will be in genetic equilibrium. Hardy-Weinberg law

Law of Genetic Equilibrium Hardy-Weinberg law Allele frequencies do not change over generations. Genotypic frequencies will remain in the following proportions p+q=1 p2: frequency of AA P2+2pq+q2=13 2pq: frequency of Aa frequency of aa

➢ Allele frequencies do not change over generations. p＋q＝1 p 2＋2pq＋q 2＝1 p 2 : frequency of AA 2pq: frequency of Aa q 2 : frequency of aa Law of Genetic Equilibrium Hardy-Weinberg law ➢ Genotypic frequencies will remain in the following proportions:

Law of Genetic Equilibrium Hardy-Weinberg law Allele frequencies do not change over generations. Genotypic frequencies do not change over generations After only one generation of random mating, population will be in genetic equilibrium

Law of Genetic Equilibrium Hardy-Weinberg law ➢ Allele frequencies do not change over generations. ➢ Genotypic frequencies do not change over generations. ➢ After only one generation of random mating, population will be in genetic equilibrium

Law of Genetic Equilibrium 1.0090.8070.60.50.403020.10 f(a)=q=q2 g(aa) P(AAL f(4)=1-q 2pq (Aa) 00.1020.3040.5 0.708091.0

f (a) = q f (A) = 1－q = q 2 Law of Genetic Equilibrium