1 / 16

25.1 Genotypic and Allelic Frequencies Are Used to Describe the Gene Pool Of a Population

25.1 Genotypic and Allelic Frequencies Are Used to Describe the Gene Pool Of a Population. Calculating genotypic frequencies F = No.AA individuals/N N: total no. of individuals F: frequency of AA alleles. Calculating allelic frequencies

griffith-gray
Télécharger la présentation

25.1 Genotypic and Allelic Frequencies Are Used to Describe the Gene Pool Of a Population

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. 25.1 Genotypic and Allelic Frequencies Are Used to Describe the Gene Pool Of a Population • Calculating genotypic frequencies • F = No.AA individuals/N • N: total no. of individuals • F: frequency of AA alleles. • Calculating allelic frequencies • Frquency of an allele = No. copies of the alleles/No. copies of all alleles at the locus in a population.

  2. 25.2 The Hardy-Winberg Law Describes the Effect of Reproduction on Genotypic and Allelic Frequencies • Hardy-Weinberg Law • Assumption: population is large, randomly mating, not affected by mutation, migration, or natural selection. • Prediction 1: the allelic frequencies of a population do not change. • Prediction 2: the genotypic frquencies stabilize.

  3. Genotypic frequencies at H-W equilibrium • p + q = 1 • p2 + 2pg + q2 = 1 • P2: homozygous dominant allele pair frequency. • Q2 :homozygous recessive allele pair frequency. • 2pq: heterozygous allele frequency.

  4. Concept Check 1 What is the expected frequency of heterozygotes in a population with allelic frequency X and Y that is in H-W? • X + Y • XY • 2XY • (X- Y)2

  5. Concept Check 1 What is the expected frequency of heterozygotes in a population with allelic frequency X and Y that is in H-W? • X + Y • XY • 2XY • (X- Y)2

  6. 25.3 Nonrandom Mating Affects the Genotypic Frequencies of a Population • Positive assortative mating: • a tendency of like individuals to mate. • Negative assortative mating: • A tendency of unlike individuals to mate.

  7. Inbreeding • Increases frequency of homozygotes in population • Rate is affected by how closely related mating pairs are

  8. Concept Check 2 What is the effect of outcrossing on a population? • Allelic frequency changes in the population. • More heterozygotes will be produced in the population. • Fewer heterozygotes will be produced. • It will reach the H-W equilibrium

  9. Concept Check 2 What is the effect of outcrossing on a population? • Allelic frequency changes in the population. • More heterozygotes will be produced in the population. • Fewer heterozygotes will be produced. • It will reach the H-W equilibrium

  10. 25.4 Several Evolutionary Forces Potentially Cause Changes in Allelic Frequencies • Mutation • Migration • Genetic Drift • Founder effect • Genetic bottle neck • Natural selection

More Related