Main Difference – Mutation vs Variation
Mutation and variation are two simultaneous events involved in the process of evolution. The main difference between mutation and variation is that mutation is an alteration in the nucleotide sequence of a gene whereas variation is any difference between individuals of a particular species. Mutations may arise due to environmental factors such as chemicals and UV. Germline mutations are inherited by the offspring. Somatic mutations occur in the ordinary body cells. Variation can occur due to mutations, genetic recombination, gene flow, genetic drift, random mating, random fertilization, and environmental factors. Variation may also cause evolution through natural selection.
Key Areas Covered
1. What is a Mutation
– Definition, Types, Features
2. What is Variation
– Definition, Types, Features
3. What are the Similarities Between Mutation and Variation
– Outline of Common Features
4. What is the Difference Between Mutation and Variation
– Comparison of Key Differences
Key Terms: Acquired Mutations, Deletions, Duplications, Environmental Variation, Genetic Variation, Hereditary Mutations, Insertions, Point Mutations, Substitutions, Translocations
What is a Mutation
A mutation is a permanent alteration in the nucleotide sequence of a gene. The size of a mutation may range from an alteration of a single nucleotide to an alteration in a large segment of a chromosome. Alterations in a single nucleotide of a gene create different alleles, which can be defined as the alternative forms of a gene. Alteration of a single nucleotide is called a point mutation. The alteration of a large segment of a chromosome may lead to alterations in multiple alleles.
Hereditary mutations and acquired mutations are the two classes of mutations. Hereditary mutations are inherited by the offspring. These mutations occur in germline cells. Therefore, hereditary mutations are also called germline mutations. Acquired mutations occur in the somatic cells due to environmental factors such as ultraviolet radiation and chemicals. These mutations are also called somatic mutations. Somatic mutations that occur in the early embryo give rise to a condition called mosaicism in which genetically different types of somatic cells can be found in the adult body.
The types of small scale mutations are substitution, insertion, deletion, and duplications.
Substitutions
Substitution is the exchange of a single nucleotide. Three types of substitutions can occur: missense mutations, nonsense mutations, and silent mutations. Some alterations of a single base pair in the nucleotide sequence of a gene may alter a single amino acid, which may ultimately result in producing a different protein, instead of the expected protein. These types of mutations are known as missense mutations. Alterations of a single base pair in the nucleotide sequence of a gene may serve as a signal to inhibit the ongoing translation. This may result in the production of a non-functional protein, consisting of a shortened amino acid sequence. These type of mutations are called nonsense mutations. Some nucleotide changes may code either for the same amino acid due to the degeneracy of the genetic code or a second amino acid with similar properties. These type of mutations are called silent mutations.
Figure 1: Effect of Substitutions
Insertions, Deletions, and Duplications
An insertion of a single or a few nucleotides will change the number of base pairs of a gene. Deletion is the removal of a single or a few nucleotides from a gene. In duplications, one or few nucleotides are copied once or several times. Insertions, deletions, and duplications result in alterations of the reading frame, leading to frameshift mutations.
Figure 2: The Effect of Frameshift Mutations
The types of alterations in chromosomal segments are translocations, gene duplications, intra-chromosomal deletions, inversions, and loss of heterozygosity. Translocations are the interchanges of the genetic parts of nonhomologous chromosomes. In gene duplication, multiple copies of a particular allele can occur, increasing the gene dosage. Intra-chromosomal deletions are the removals of segments of chromosomes. Inversions change the orientation of a chromosome segment.
Figure 3: Chromosomal Mutations
Heterozygosity of a gene can be lost due to the loss of an allele in one chromosome by deletion or genetic recombination. The chromosomal mutations are shown in figure 3.
What is Variation
Variation is any difference between individuals or group of individuals in a particular species. Genetic differences cause genotypic variations, and environmental factors cause phenotypic variations. Variations can be seen in the metabolism, physical appearance, mode of reproduction, fertility, behavior, and mental ability. Genetic variation and environmental variation are the two types of variations.
Genetic variation may occur due to either germline mutations or genetic recombination, which functions at meiosis. The other causes of genetic variation are gene flow, genetic drift, random mating, and random fertilization. Germline mutations and gene flow may introduce new genes to the population. Genetic recombination, random mating, and random fertilization cause the reshuffling of alleles.
Figure 4: Morphological Variation of Dogs
Environmental variation arises due to the effect of environmental factors such as diet, light, moisture, temperature, minerals, exposure, climate, culture, and lifestyle. That means the phenotype of an individual is determined by the environment. The most precise example of environmental variation is the difference of phenotypes between identical twins. The morphological variation of dog due to genetic variation is shown in figure 4.
Similarities Between Mutation and Variation
- Mutation and variation introduce different characters to a population.
- Both mutation and variation cause evolution of a particular species through natural selection.
Difference Between Mutation and Variation
Definition
Mutation: A mutation is a permanent alteration in the nucleotide sequence of a gene or a part of a chromosome.
Variation: Variation is any difference between individuals or group of individuals belonging to a particular species.
Significance
Mutation: A mutation may affect a single individual.
Variation: Variation can be seen in a group of individuals.
Causes
Mutation: Mutations occur due to the errors in DNA replication and exposure to UV or chemicals.
Variation: Variation can occur due to mutations, genetic recombination, gene flow, genetic drift, random mating, random fertilization, and environmental factors.
Types
Mutation: Hereditary mutations and acquired mutations are the two types of mutations.
Variation: Genetic variation and environmental variation are the two types of variation.
Correlation
Mutation: A mutation causes an alteration of a genotype in an individual.
Variation: Mutations cause variation.
Conclusion
Mutation and variation are two causes of evolution. A mutation is an alteration of the nucleotide sequence of a gene or part of a chromosome. Errors in DNA replication and environmental factors such as UV and chemicals may cause mutations. Mutations can be either hereditary or acquired. Mutations cause genetic variation among individuals of a particular population. Variation is any difference between individuals in a population. Other than mutations, genetic recombination, gene flow, genetic drift, random mating, random fertilization, and environmental factors cause variations. The main difference between mutation and variation is the influence of each factor towards evolution.
References:
1.” What is a gene mutation and how do mutations occur? – Genetics Home Reference.” U.S. National Library of Medicine. National Institutes of Health, n.d. Web. Available here. 29 July 2017.
2. “What kinds of gene mutations are possible? – Genetics Home Reference.” U.S. National Library of Medicine. National Institutes of Health, n.d. Web. Available here. 29 July 2017.
3. “Mutation.” Wikipedia. Wikimedia Foundation, 28 July 2017. Web. Available here. 29 July 2017.
4. “Genetic Variation.” Boundless. N.p., 26 May 2016. Web. Available here. 29 July 2017.
5. “Environmental variation.” BBC – GCSE Bitesize. N.p., n.d. Web. Available here. 29 July 2017.
Image Courtesy:
1. “Point mutations-en” By Jonsta247 – Own work (GFDL) via Commons Wikimedia
2. “Frameshift mutations (13080927393)” By Genomics Education Programme – Frameshift mutations (CC BY 2.0) via Commons Wikimedia
3. “Chromosomes mutations-en” By GYassineMrabetTalk (Public Domain) via Commons Wikimedia 4. “Dog morphological variation” By Mary Bloom, American Kennel Club – (CC BY-SA 4.0) via Commons Wikimedia
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