What is Genetic Variation?

Introduction

The study of hereditary variation is known as Genetics. Human genetics is the scientific study of inherent human variation.

The genetic makeup of organisms within a population change is known as genetic variation. Genetic variation can be beneficial in the below-mentioned fields:

• Natural selection can use genetic variation to increase or decrease the frequency of alleles present in the population, an influential factor in evolution.
• Mutation (which can produce whole new alleles in a population), random mating, random fertilisation, and linkage among homologous chromosomes during meiosis can contribute to genetic variation.
• Genetic variation is beneficial to a population as it allows specific individuals to adapt to their surroundings while still allowing the population to survive.

Table of Contents

• Meaning of Genetic Variation
• Types of Genetic Variation
• Causes of Genetic Variation
• Genetic Variation Examples
• Frequently Asked Questions (FAQs)

Meaning of Genetic Variation

The genetic composition of organisms within the population changes is denoted as genetic variation. Genes are inherited DNA segments that contain protein-coding information. Alternate forms of genes, also known as alleles, decide various features which can be passed down from parents to kids.

Genetic variation is fundamental for natural selection since it can only enhance or reduce the frequency of alleles. The following factors contribute to genetic variation:

• Mutation
• Random fertilisation
• Random mating between organisms
• Crossing over among chromatids of homologous chromosomes during meiosis

Variation permits certain members of a population to adapt to changing conditions. Because natural selection mainly affects phenotypes, more genetic diversity within a population usually leads to more phenotypic variability.

Genetic variation is beneficial because it allows certain individuals, and so populations, to survive in a changing environment. Cheetah populations in the wild have extremely low genetic variation. Because wild cheetahs are endangered, their genetic diversity is extremely limited. Because of their low genetic diversity, they are more sensitive to disease and are more likely to pass on harmful recessive genes; only around 5% of cheetahs reach adulthood.

Types of Genetic Variation

1. Single Base-Pair Substitution

A mutation in DNA or RNA involves the substitution or replacement of a single nucleotide base with another. It is also referred to as single nucleotide polymorphism (SNP) and can be of any nucleic acid substitution:

• Transition

A small-scale mutation in which a purine is replaced by another purine (e.g. A→G) or a pyrimidine is replaced by another pyrimidine (e.g. T→C).

• Transversion

A modest mutation in which a purine is replaced by another pyrimidine (e.g. A→C) or a pyrimidine is replaced by another purine (e.g. T→G).

2. Insertion or Deletion

‘Indel’ refers to the insertion or deletion of a single length of DNA sequence ranging in length from two to hundreds of base pairs.

3. Structural Variation

Structural variation (SV) is a term used to describe an area of DNA that is 1 kb or larger and can include inversions, balanced translocations, and genomic imbalances (insertions and deletions), which are also known as copy number variants (CNVs).

Causes of Genetic Variation

• Sexual reproduction: Sexual reproduction encourages genetic variation by resulting in various gene combinations. Alleles are segregated and randomly united during fertilisation, resulting in genetic variation. Crossing over or swapping gene segments in homologous chromosomes during meiosis also results in the genetic recombination of genes.
• DNA mutation: A mutation occurs when the DNA sequence changes. These differences in gene sequences can be beneficial to an organism under certain circumstances. The majority of mutations that generate genetic variation produce features that are neither advantageous nor disadvantageous. Mutations affect genes and alleles in a population, resulting in genetic variation.
• Gene flow: Gene flow, also known as gene migration, occurs when organisms migrate to a new habitat and introduce new genes into the population. The availability of novel alleles in the gene pool allows for new gene combinations. The emigration of organisms out of a community can also change gene frequencies. New creatures entering a community might aid organisms in adapting to changes in the environment. The loss of genetic variation could result from organisms leaving a group.

Genetic Variation Examples

Sexual selection is prevalent in nature, with animals choosing mates with desirable characteristics. Because females prefer to mate with males who have more desirable characteristics, these genes become more abundant in a community over time.

Hair colour, skin colour, freckles, dimples, and blood type are examples of genetic variations which exist in the human population.

Altered leaves of predatory plants and the formation of flowers that resemble insects attracting plant pollinators are examples of genetic variations in plants. Gene flow is a common source of gene variation in plants.

Cheetahs with stripes, animals that pretend to be dead, albinism, snakes that fly, and animals that imitate leaves are all genetic variations in animals. These differences allow the animals to adapt better to their surroundings.

Further Reading:

• What is Genetic Diversity?
• Variation – Organisms And Their Copies
• What Is Variation and Its Types?
• What Are The 3 Types Of Genetic Variation?
• Difference between Substitution, Insertion and Deletion Mutations