Genetic Diversity: Definition, Types, and Examples

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Genetic Diversity Definition

Genetic diversity is defined as the sum of different alleles within a species or population. Both the huge number of distinct species and the variety within a species are referred to as genetic diversity.

What is Genetic Diversity?

Individuals within each species have their own unique collection of genes. A gene is a hereditary unit that allows future generations to inherit the characteristics of their parents. The nucleotide sequence of the DNA strands packed in chromosomes is referred to as genes.

Since these genes govern the differences and similarities across various species, they are responsible for the manifestation of their distinguishing traits. Different genes would be accountable for the variance among a population’s members.

Human populations, for example, are made up of people with a variety of physical characteristics that reflect their genetic diversity. Genetic variety may be found within species as well as between them. Different breeds of dogs, for example, may make up a dog population. 

Genetic Diversity, Variability, and Variation

The ability of a population to create creatures with various genotypes is known as genetic diversity. In a population, genetic diversity is defined as the occurrence of a variety of alleles with varied distribution frequencies. Individual (i.e., between individuals) or species-level genetic variation is simply defined as the variance of genomes (i.e. between species populations).

Mutations can result in the emergence of mutants or variations; mutations can induce the emergence of mutants or variants. Sexual reproduction and genetic drift, in addition to mutation, are further processes that lead to genetic diversity. The term “genetic diversity,” on the other hand, refers to the extent of such diversity.

Genetic Diversity and Biodiversity

In an ecosystem, genetic variety is the most important contributor to biodiversity. The phrase biodiversity refers to the biological variety of life on Earth, which encompasses a wide range of microbes, plants, and animals, as well as their genes and the settings or habitats in which they live.

Genetic diversity is defined by many academics as the degree and extent of genetic variety across populations, whereas biodiversity is defined as the diversity of all species in a given environment at a given period. “Ecosystem diversity” and “species diversity” are two more words that are important to this issue.

The existence of diverse ecosystems in a particular location is described as ecosystem diversity; species diversity is defined as the presence of different species in a given region. The variety of their DNA is the source of all variations within species.

A healthy environment requires a diverse range of species. Genetic diversity contributes to the degree of these differences. Species with more variety have a reduced risk of going extinct. The higher the genetic variety within a species, the better chance it has of surviving. Conversely, the smaller a species’ genetic diversity, the lower its chances of survival.

This is because undesirable characteristics, such as hereditary illnesses, can spread throughout a community. Because of the high likelihood of inheriting the gene causing it owing to a limited varied gene pool, when left to reproduce, the children are likely to display the undesirable characteristic as well.

The environment, in addition to genetic variety, is a source of diversity within species or populations. The degree of diversity among individuals in a population is determined by the interaction of the environment and genes. A population might be made up of a small number of people or a big number of people.

Some of these individuals may be able to mate and have children. The amount of genetic diversity between people varies. Individuals have distinct genes owing to minor variations in their DNA sequences, therefore genetic diversity exists within a community.

Mutations can cause changes in DNA sequences, resulting in distinct alleles. Allele variation influences an organism’s adaptability, physiological development, and capacity to survive and reproduce in a variety of environments.

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Importance of Genetic Diversity

Genetic variety is essential because it ensures that specific groups of people, species, or populations can adapt to changing environmental conditions. Apart from dealing with environmental factors, genetic variety gives them the capacity to fend off new illnesses and outbreaks.

Low genetic diversity, on the other hand, may make a species more vulnerable to biotic and abiotic stressors like illness and drought, putting it in danger of extinction in the long term. Genetic variety is a result of genetic variance, as previously stated.

Genetic diversity is important for every species because it helps them to adapt to changing environmental conditions. As a result, the species is less likely to go extinct and so has a longer lifespan. As a result, genetic diversity aids the species’ adaptation, survival, and evolution.

Because the more variegated the genes are within a population, the more diversified the alleles will be, the variety of the gene pool allows the species to thrive. There may be certain genotypes among them that enable certain individuals to become more suited and therefore survive a specific set of environmental stresses.

As a result, future generations will have an advantage because they may inherit alleles that allow them to survive specific circumstances. This is how it could contribute to their species’ survival.

Long-term survival of species is determined by their capacity to adapt to changing environmental circumstances. The genetic diversity among organisms is essential for long-term survival. The tolerance of various people within the same group to the same stressor, for example, varies.

Some people with particular genes can survive in an area with a high level of pollution, whereas others cannot. Surviving people can pass on the genes that make them resistant to contaminants to their children, improving the population’s ability to adapt to changing environmental conditions in the future.

A greater diversity of species leads to a greater diversity of habitat. Ecosystem functions and structure are maintained through species diversity. Ecosystem variety allows ecosystems to rebound from the consequences of changes brought on by natural disasters or abrupt changes.

Low-diversity ecosystems have a difficult time resuming their usual function. Instead, their function might be permanently altered, resulting in a shift in species composition and a significant loss of natural resources.

The evolutionary process can be deduced from genetic diversity. It is regarded as the basic material and key to evolution, as well as species adaptation to change the world. Some species may not survive in the long run if they do not develop and adapt to environmental changes.

Small populations require genetic variety because they may lose it over time due to the influence of genetic drift. Fixation and drift of one allele can lead to the loss of another, resulting in genetic diversity loss over time. When two individuals in a small population mate, they are more likely to have the same allele and transmit it down through the generations, resulting in the fixation of an allele and a reduction in genetic variation.

Large populations, on the other hand, preserve genetic variety by preserving their genetic material. As a result, when a population is subjected to the bottleneck effect, it is more likely than large populations to lose genetic diversity. Because large animals generate a smaller number of offspring, genetic diversity is more essential to them than it is to small mammals.

Conservation genetics is an essential issue when it comes to saving genetic variation among threatened species. Because low rates of genetic variety reduce population fitness, extinction of a species is less likely if significant genetic diversity exists among populations. One of the reasons contributing to the species’ extinction danger is its decrease.

Finally, genetic diversity causes morphological, physiological, and behavioural differences across species, groups, and individuals, affecting ecosystem services and ecological functions. As a result, the loss of genetic diversity within species populations can have an effect on both ecological services and human well-being.

Examples of Genetic Diversity

Discover the genetic diversity of living species that reproduce sexually or asexually. Genetic diversity is less likely in asexually reproducing species. This is because of the accessible gene pool, which in this scenario would only be based on one parent, will limit it.

In obligatory parthenogenesis, for example, the mother produces clones as offspring. Cloning means that the babies will have the same genes as their mother. This is due to the fact that in the absence of a male partner, the mother may create progeny.

As the clones’ gene pool is restricted to their mother’s genome, any vulnerability to illnesses or genetic abnormalities can be predicted. In sexually reproducing animals, however, genetic diversity is higher. Mating allows for gene variety in sexual reproduction since it involves not just the mother’s but also the father’s genome.

Humans have a lot of genetic variety. Humans have different eye colours, hair colours, skin colours, heights, and so forth. Identification procedures such as fingerprinting rely on the diversity of human populations. Human genetic diversity is particularly high in distant communities, when human population variety is modest in comparison to overall human variation.

Factors of Genetic Diversity

Four phenomena in evolution impact genetic diversity: mutation, genetic drift, gene flow, and natural selection. Only mutations, on the other hand, can create totally new alleles.

1. Mutations

Changes in the nucleotide sequence of DNA are known as mutations. Mutations are caused primarily by the replacement or alteration of genes and chromosomes. Mutations can result in the emergence of new alleles, altering the genetic structure of a population.

Mutations that occur by chance are uncommon. They have a minimal influence on modifying a population’s genetic structure, and they have a negligible effect in short periods of time. That is why evolution is not controlled by mutations. Mutations, along with other adaption processes that impact evolution, can, nonetheless, be a significant source of genetic variation in a population.

Mutations can arise in either a somatic cell or a gametophytic cell in multicellular organisms (gametes). Mutations in somatic cells can disrupt mitosis, which can lead to tumour development. These mutations, on the other hand, are not passed on through the generations.

Gamete mutations, on the other hand, are inherited mutations that may be passed on to children. In the long run, these mutations have an impact on genetic diversity.

2. Genetic Drift

Genetic drift is a random shift in the frequency of a particular allele in a population from generation to generation caused by chance sampling events, which is less prominent in large populations. The random selection of some alleles to be inherited by children causes genetic drift.

Because changes in allele frequencies can generate more substantial disparities across distinct populations, it influences genetic diversity by fixing certain alleles and losing others. Small populations are more affected by genetic drift than big populations because the likelihood of the influence of fixed or lost alleles appearing in small populations is higher. It is not selective for helpful genes; on the contrary, it may repair bad or fatal genes while losing good ones.

Because new recessive alleles may be fixed, genetic drift adds to genetic diversity among populations. It affects populations that have been exposed to events that cause a rapid reduction in population size, such as natural disasters that diminish genetic variety in populations. The bottleneck effect describes how natural calamities affect a population.

For the evolutionary process, the bottleneck effect is critical. The evolution of various species is heavily influenced by changes in population size throughout time. Bottleneck impacts include those induced by climate changes, resource constraints, natural disasters (such as earthquakes), and so on. In most cases, population bottlenecks reduce genetic variety within a group.

3. Gene Flow

Gene flow, also known as gene migration, is the process of alleles being passed down across populations. Gene flow refers to the production of new generations with a certain allele that has been passed down from a donor population to a recipient population. This allele is found in each of them at different rates.

Pollen, for example, may be carried to far locations by wind, which carries alleles from one group to another with a low allele frequency. A species, on the other hand, is the biggest unit within which gene flow can easily occur. Gene flow is a critical method for maintaining genetic variety and contributing to the evolutionary process by allowing genes to migrate between populations with differing allele frequencies.

When the new allele was not previously detected in the receiving group, this factor can cause novel alleles or chromosomal rearrangements. Increased genetic diversity and the introduction of novel alleles among populations are two impacts of gene flow.

4. Natural Selection

Natural selection refers to the process in which a population’s gene pool evolves as individuals who can adapt to changes in the environment reproduce. During evolution, it is an essential mechanism of population adaptation to environmental circumstances. Individuals can use physiological strategies to resist environmental influences in the short term.

Long-term resistance, on the other hand, necessitates altering the genetic mix of the population. Natural selection refers to the transfer of beneficial alleles from one generation to the next, resulting in increased adaptability. Natural selection favours better suited organisms while eradicating the less adapted.

As a result, the basis of evolution across species is genetic material changes along with natural selection. The removal of the population’s less adaptable alleles eliminates the more vulnerable creatures that can’t cope with environmental changes.

As a result, natural selection affects the frequency of alleles in a population by altering the contribution of people in subsequent generations, therefore modifying gene frequencies. Sexual selection occurs as a result of either direct rivalry for fertilisation among men or sperm (same-sex members) or attraction between different sexes.

Sexual selection has an impact on genetic diversity and, as a result, genetic evolution. To maintain genetic variety over generations, genes from both men and females must be passed down through the generations.

Conservation of Genetic Diversity

Many dangers are posed to genetic diversity. As a result, the worldwide community is dedicated to preserving biodiversity at all levels, including species genetic diversity. Conservation genetics focuses on preserving genetic variety at various levels as well as assessing and monitoring population conservation plans.

They are primarily concerned with the preservation of many factors that influence genetic variety, such as genetic variation patterns, species, populations, and genotypes. In the near term, genetic variety preservation preserves reproductive capability, but in the long term, it preserves species’ ability to adapt and evolve.

The preservation of genetic diversity among endangered and uncommon species is one of the major aims of conservation genetics. The conservation of genetic variety is mediated by three components:

(1) identifying the goal of conservation,

(2) understanding the genetic diversity of populations, and

(3) using conservation strategies.

The best practical gene conservation approach for a species is determined by local characteristics, population genetic structure, and geographic range size. For example, forest tree genetic variety is preserved by growing populations in their natural habitat, preserving germplasm in a cold climate, or planting trees in diverse locations outside of their origin.

For all living species, genetic diversity conservation is the same. However, different approaches are used based on the conservation aim, distribution of the conservation item, and biological type. As a result, understanding the differences between and within populations is critical for obtaining information for managing the conservation of various populations.

Genetic Diversity References

What is genetic diversity?

Why is Genetic Diversity Important?

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