Biology · MU Sofia

36. Population biology and genetics. Concept of population. Phenotype, genotype and gene frequences. Types of mating. Hardy – Weinberg law.

Explains phenotype, genotype and allele frequencies and how each is calculated, with worked examples such as albinism and the MN blood group. It then sets out the Hardy-Weinberg law, its five assumptions, and the forces that disrupt equilibrium, including three mnemonics and a key-terms table. A closing section covers mutation rates and their role as the source of new genetic variation.

Inside: 5 sections · 3 labelled pictures · 1 table · 10 min

Topic 36 of 64 in the MU Sofia syllabus for Biology (Dental Medicine, Year 1). The free AceMed note covers it in 5 sections, about 1,373 words (10 min of reading).

In this note

  1. Phenotype, Genotype and allele frequencies. Hardy - Weinberg Law
  2. Key Concepts in Population Genetics
  3. Phenotype, Genotype, and Allele Frequencies
  4. 🔑 Key Concepts & Definitions
  5. Factors Influencing Allele Frequencies: Mutations, Migrations, Natural selection

Phenotype, Genotype and allele frequencies. Hardy - Weinberg Law

  • Population genetics is the study of how genes and alleles behave in populations and how their frequencies change over time.
  • It focuses on factors like natural selection, mutation, gene flow, and genetic drift which influence genetic variation.
  • Additional influences include recombination, population subdivision, and population structure.
  • Evolution at the population level starts with a change in allele frequencies across generations.
  • A population is defined as a group of individuals of the same species living in a shared geographical area at the same time, who can interbreed.
  • Evolution occurs at the population level, making it the smallest unit capable of evolving.

Key Concepts in Population Genetics

  • The gene pool is the complete set of all alleles at all loci within a population.
  • Natural selection refers to differences in survival and reproduction due to variations in traits among individuals.
  • Genetic drift refers to random fluctuations in allele frequencies in small populations due to chance events, not natural selection.

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