Population Genetics and Allele Frequencies

Gene Pools:
- A gene pool encompasses all the alleles within a population.
- Gametes from a generation combine randomly into a single group called the gene pool.

Equation:
- The fundamental equation is $p^2 + q^2 + 2pq = 1$ , analogous to a chi-square test.
- 'p' and 'q' represent the frequencies of two different alleles in a population.
Example Calculation:
- If allele A1 has a frequency of 0.7 and allele A2 has a frequency of 0.3:
  - $p^2$ (A1A1) = $(0.7)^2 = 0.49$
  - $q^2$ (A2A2) = $(0.3)^2 = 0.09$
  - $2pq$ (A1A2) = $2 \times 0.7 \times 0.3 = 0.42$
  - The sum of these frequencies equals 1 (0.49 + 0.09 + 0.42 = 1).

Cardiopulmonary Example:
- If parental allelic frequencies are A1 = 0.7 and A2 = 0.3, offspring will reflect these same frequencies.
Calculating Allele Frequencies:
- A1 allele frequency (p) = 0.7
- A2 allele frequency (q) = 0.3
- The frequency remains constant from generation to generation if Hardy-Weinberg equilibrium assumptions are met.

Environmental Factors:
- Genetic drift can alter allele frequencies.
Mutations:
- Mutations introduce new alleles, changing frequencies.
Nonrandom Mating:
- Selective mating preferences can shift allele frequencies.
Immigration and Emigration:
- Immigration introduces new alleles, while emigration removes alleles from the population.

Conditions for Equilibrium:
- The Hardy-Weinberg equilibrium provides predictions based on specific assumptions. When these assumptions are violated, allele frequencies change.
Factors Causing Changes:
- Non-random mating
- Natural selection
- Genetic drift
- Gene flow
- Mutations

Real-world Connections:
- Scientific concepts can be related to macro-world events.
- Example: Restricting immigration affects the gene pool by limiting the introduction of new alleles.
Gene Pool Dynamics:
- The total number of alleles (e.g., A1 and A2) in a gene pool remains constant across generations if equilibrium is maintained.