These mutations are passed on to subsequent generations through DNA replication.Ĭhromosome mutations may alter the structure of a chromosome or the number of chromosomes in a cell. This results in the production of faulty proteins. Base-pair insertions/deletions cause frame shift mutations in which the frame from which DNA is read during protein synthesis is shifted. In a point mutation, a single nucleotide base is changed altering the gene sequence. Gene mutations typically occur as either point mutations or base-pair insertions/deletions. Mutations may impact individual genes or entire chromosomes. Although mutations produce changes in the genotype of a population, they may or may not produce observable, or phenotypic changes. These changes alter genes and alleles leading to genetic variation in a population. Mutations are permanent changes in the gene sequence of DNA. One of the conditions that must be met for Hardy-Weinberg equilibrium is the absence of mutations in a population. In the development of this equation, Hardy and Weinberg extended established Mendelian genetics principles of inheritance to population genetics. In this equation, p 2 represents the predicted frequency of homozygous dominant individuals in a population, 2pq represents the predicted frequency of heterozygous individuals, and q 2 represents the predicted frequency of homozygous recessive individuals. It is useful for comparing changes in genotype frequencies in a population with the expected outcomes of a population at genetic equilibrium. This equation, p 2 + 2pq + q 2 = 1, is also known as the Hardy-Weinberg equilibrium equation. Based on the idealized conditions, Hardy and Weinberg developed an equation for predicting genetic outcomes in a non-evolving population over time. As such, evolution does happen in populations. The conditions required for genetic equilibrium are idealized as we don't see them occurring all at once in nature. Natural selection must not occur to alter gene frequencies.Mating must be random in the population.A very large population size is required to ensure allele frequency is not changed through genetic drift.No gene flow can occur to increase variability in the gene pool.Mutations must not occur to introduce new alleles to the population.These five main conditions are as follows: This model is based on five main assumptions or conditions that must be met in order for a population to exist in genetic equilibrium.
They constructed a model for predicting genotype and allele frequencies in a non-evolving population. The Hardy-Weinberg principle was developed by the mathematician Godfrey Hardy and physician Wilhelm Weinberg in the early 1900's. CNX OpenStax/Wikimedia Commons/CC BY Attribution 4.0