Population Genetics: Central Dogma, Allele Frequency Equation and Gene Pools

Welcome to My AP Biology Thoughts podcast, my name is Shriya and I am your host for episode 5 called “Population Genetics: Central Dogma, Allele Frequency Equation and Gene Pools.” Today we will be discussing the definitions of all of those concepts as well as a few examples to go along with them. Then, we will connect all of that to the overarching topic of evolution. Hope you enjoy!

Segment 1: Introduction to Population Genetics: Central Dogma, Allele Frequency Equation and the Gene Pool

Introduce the episode topic

Include definitions and vocabulary

• Will be discussing the topic of population genetics which is the study of genetic variation within a population and looking into changes in the frequencies of genes and alleles in populations over time
• Natural selection is one of the most influential factors that can affect a population’s genetic composition
• Central dogma of biology is when the instructions contained in DNA are converted into a functional product, a phenotype
• DNA, contains the genes that determine who you are, and proteins determine the structure and function of all your cells
• It describes the two-step process, transcription and translation, of how information in genes flow into proteins, creating a string of amino acids called polypeptides
• The DNA has the information which is used by the RNA to make the proteins
• The Allele Frequency Equation: an allele is a version of a gene and a heritable unit that controls a particular feature of an organism
• The allele frequency refers to how often a particular allele appears in a population
• An equation called the Hardy-Weinberg equation is used to calculate the genetic variation in a population: p^2 + 2pq + q^2
• p^2 and q^2 are the allele frequencies of the homozygous recessive and homozygous dominant, and 2pq is the allele frequency of the heterozygous genotypes
• To get p and q individually, you calculate actual/total # of alleles
• With this knowledge, you are able to calculate the total allele frequencies using the equation p + q = 1
• The gene pool is calculated using the equation just mentioned, p + q = 1 since it is the sum of both allele frequencies
• A gene pool is the collection of different genes within an interbreeding population, and refers to its genetic diversity
• The larger the gene pool, the greater genetic diversity, and the better a population is able to withstand environmental challenges

Segment 2: Examples of Population Genetics

Have a natural transition into an example… no need to say “segment 2”