5.5 Population Genetics

Gene Pool:

• Population genetics is concerned with determining the relative proportions of the various genotypes present in a population, from which the relative proportions of alleles can be calculated. This is known as allele frequency.
• A population of organisms that sexually reproduce contains a large amount of genetic variation called a gene pool. 
• Each organism contains just one of the many possible sets of genes that can be formed from a gene pool.
• The gene pool remains stable if the environment is stable.
• If the environment changes the advantageous genotypes are selected for and the disadvantageous genotypes are selected against.
• Therefore the gene pool is constantly changing.
• Alleles may become more and less common, or disappear from the gene pool altogether.
• The Hardy-Weinberg principle states that in a large, randomly mating population, assuming the absence of migration, mutation and selection, the gene and genotype frequencies remain constant. This is, the proportion of dominant and recessive alleles of a particular…