Hardy-Weinberg equation | Biomolecules | MCAT | Khan Academy
Courses on Khan Academy are always 100% free. Start practicing—and saving your progress—now: https://www.khanacademy.org/science/ap-biology/natural-selection/hardy-weinberg-equilibrium/v/hardy-weinberg This equation relates allele frequencies to genotype frequencies for populations in Hardy-Weinberg equilibrium. Created by Sal Khan. MCAT on Khan Academy: Go ahead and practice some passage-based questions! About Khan Academy: Khan Academy offers practice exercises, instructional videos, and a personalized learning dashboard that empower learners to study at their own pace in and outside of the classroom. We tackle math, science, computer programming, history, art history, economics, and more. Our math missions guide learners from kindergarten to calculus using state-of-the-art, adaptive technology that identifies strengths and learning gaps. We've also partnered with institutions like NASA, The Museum of Modern Art, The California Academy of Sciences, and MIT to offer specialized content. For free. For everyone. Forever. #YouCanLearnAnything Subscribe to Khan Academy’s MCAT channel: https://www.youtube.com/channel/UCDkK5wqSuwDlJ3_nl3rgdiQ?sub_confirmation=1 Subscribe to Khan Academy: https://www.youtube.com/subscription_center?add_user=khanacademy
Hardy-Weinberg equation | Biomolecules | MCAT | Khan Academy
Understanding the Hardy-Weinberg Principle
Introduction to Allele Frequencies
- The Hardy-Weinberg principle is introduced as a framework for understanding allele frequencies in populations, particularly regarding homozygous and heterozygous traits.
Assumptions of the Hardy-Weinberg Principle
- Key assumptions include no natural or unnatural selection affecting allele frequencies, ensuring stability across generations.
- It is assumed that there are no mutations altering alleles from one generation to the next.
- Large population sizes are necessary to maintain stable allele frequencies, avoiding significant fluctuations seen in smaller groups.
Mathematical Foundations
- The sum of the frequency of dominant (p) and recessive (q) alleles equals 100% (or 1), establishing a foundational equation: p + q = 1.
- This relationship allows for calculating probabilities related to homozygous and heterozygous genotypes based on allele frequencies.
Algebraic Representation
- Squaring both sides of the equation leads to p² + 2pq + q² = 1, where:
- p² represents the probability of being homozygous dominant.
- q² indicates the probability of being homozygous recessive.
Understanding Genotype Probabilities
- The term p² reflects the likelihood of randomly selecting two dominant alleles from a population.
- Conversely, q² signifies the chance of obtaining two recessive alleles through random selection from parents.
Understanding Allele Frequencies in Populations
The Probability of Genotypes
- The discussion centers on the probability of being a heterozygote, highlighting its significance in understanding allele frequency within a population.
- By making certain assumptions and reasoning through allele frequencies, a powerful expression is derived that aids in analyzing genotype frequencies.
- The sum of probabilities for homozygous dominant, heterozygote, and homozygous recessive individuals equals 100%, illustrating the completeness of genotype distribution.
- This foundational concept emphasizes how different genotypes contribute to overall genetic diversity within populations.