Introduction
Genetics is the study of chromosomes, DNA, and genetic materials, which are the structural and functional units of life and are of great importance in identifying an individual and treating or preventing many genetic disorders that can be caused due to mutation in the genes. To prevent disorders like Down syndrome and other genetic disorders, it is very important to study a person's genetics, and measured genetic variations can help determine any addition, deletion, or alterations in an individual's genes. Various scientists use different methods to measure relative genotype frequency, and relative allele frequency is considered one of the most popular methods. These studies help in determining the degree of variations using mathematical formulas.
What Is Genetic Variation?
Genetic variation can be defined as the difference in DNA sequences among the individuals of the same species and the offspring that develop from the same parent species within a population or is identified by evaluating the number of pleomorphic gene loci. This genetic variation results due to an alteration in the genotype (genetic makeup of an individual) or phenotype (set of observable characteristics of an individual) of a person. Genetic variation is the reason why every individual looks different.
What Is a Measured Genetic Variant?
A measured genetic variant can be described as the factors that are altered or mutated while passing on the genetic material from parents to the offspring, which results in changes in the features and characteristics of every individual.
What Are the Types of Measured Genetic Variants?
Measured genetic variants are categorized into the following four types which are:
1. Single-Nucleotide Polymorphisms or Single-Nucleotide Variations (SNP/SNVs): This is a phenomenon in which a single nucleotide or a specific sequence in the DNA is altered or replaced. This can be a reason for the variation in the characteristics of different individuals. The effect of these alterations depends on the site of replacement. This can lead to genetic disorders, frequent infections, and compromised immunity. These SNPs are present between two genes and are very helpful to researchers as they help determine various disorders.
2. Indels: The term originates as an abbreviation of insertion or deletion. This describes the addition or deletion of the bases in the DNA sequence. Indel is one of the common measures of human variation and encodes for 15 to 20 percent of the variation in humans.
3. Copy Number Variations: This can be defined as the repetition of genomic sequence. The repetition of these sequences is different in every individual and is based on the process called duplication and deletion. These variations are classified based on the lengths of replication as
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Short Duplications: The number of nucleotides repeated is around two or three. The most commonly known short duplication is CAG (Cytosine-Adenine-Guanine) nucleotide which is responsible for neurological disorders like Huntington's disease. These duplications are considered to be caused due to errors during replication.
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Long Duplications: Entire gene sequence is repeated. The repetition of the complete gene immediately affects the expression of the gene characteristics. This effect is mainly encountered.
4. Translocations and Inversions: These processes occur when the DNA is replicated during the cell cycle. Translocation is the transfer of genetic material from one strand of DNA to another. Whereas inversion is a process that can occur only when a strand rotates 180 degrees as the genetic material from one locus is attached to another of the same DNA.
How Is Genetic Variation Measured?
Genetic variations are nothing but differences in appearance and characteristic behaviors of individuals; these variations occur due to the presence of different alleles and their frequency of occurrence in the genes. The higher the variations more would be the more variation in the allele. Scientists use certain formulas and methods to calculate these variations, which are as follows;
These genetic variations can be measured with the help of the following frequencies:
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Relative Phenotype Frequency: This helps determine and differentiate individuals with identical phenotypes in a population. Relative phenotype frequency is calculated with the help of a formula, relative phenotypic frequency = rate of occurrence of a phenotype ÷ total population.
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Relative Genotype Frequency and Relative Allele Frequency: This is the most commonly used method and is considered more precise. This method uses a genotypic record of a particular population and calculates the percentage of individuals with a specific genotype. It is believed this method helps in obtaining an accurate value of genetic variation.
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Relative Allele Frequency: It is also considered one of the important measures of genetic variation.
What Is the Impact of Genetic Variation?
Genetic variation plays an important role in evolution, genetic variations alter the traits of the individuals, and the beneficial traits are passed on to the next generations. This is the process that has helped in evolution for ages. It is the genetic makeup or the variation that helps make every individual unique; therefore, it can be said that an individual's identity is because of the genes they possess.
Conclusion
Genes are a person's genetic identity, and variation in these genes can only make every individual unique in their looks and behaviors. These variations depend on the amount of alteration or difference in the genomes of an individual. Scientists have used various techniques to determine and measure these genetic variations. These techniques include Relative phenotype frequency, relative genotype frequency, and relative allele frequency. Variants of genetics can be termed as the DNA and the allele even the bases and proteins present in the DNA play an important role.
