What is Genetic Diversity? Examples, Threats, Conservation

We have millions of different species in our natural world, which look distinct from one another. While animals like lions and tigers may appear identical and have similar characteristics, genetic diversity still differentiates one from the other. 

Genetic diversity refers to all the biological differences that occur within a species. Genetic diversity is a fundamental aspect that allows species to adapt to an environment. It ensures the adaptability, resilience, and survival of many species. 

In this article, we will look into the concept of genetic diversity in biodiversity, its importance, the consequences of genetic diversity loss, and the conservation of genetic diversity.

Quick links to genetic biodiversity:

What is Biodiversity?

Before we look at genetic diversity, let’s look at the concept of biodiversity. Biodiversity or biological diversity is all the different kinds of life you will find on our planet. 

Various living organisms and plants work together in ecosystems to create a balanced world and support life on Earth. Biodiversity is significant for ecosystem services, ecosystem stability, and the overall health of our planet.

Biodiversity is sorted into three groups. It encompasses ecosystem diversity, genetic diversity, and species diversity.

Ecosystem Diversity

Ecosystem diversity refers to a combination of living and nonliving organisms and how they interact. It involves different ecosystems, such as forests, grasslands, oceans, and deserts. In the field of biology, ecosystem diversity describes various levels of diversity within living systems. Thanks to ecosystem diversity, our ecosystems can recover from changes like natural disasters. 

Without diversity, our ecosystem may suffer loss of natural resources and lead to changes in species composition. Ecosystem diversity also contributes to the functionality of ecosystems. This includes the provision of habitats, nutrient cycling, and climate regulation. 

Species Diversity

It refers to biodiversity at the most fundamental level. It is the number and variety of species within a given ecosystem or region. Species diversity includes all species, from microorganisms to plants and animals. Species diversity covers the number of species present (species richness) in an ecosystem and the relative abundance of each species (species evenness). 

Various ecological factors, including climate, habitat diversity, genetic diversity, competition for resources, and the interactions between species, influence species diversity. 

Genetic Diversity

It refers to the variation in the genetic composition among individuals within a population of a single species. This variation happens due to various factors like mutations, recombination, population size, and natural selection, among other factors. 

All three types of biodiversity are intertwined for a well-balanced planet. However, genetic diversity is critical to how different species adjust and survive changes in our planet.

What is Genetic Diversity?

Genetic diversity refers to the total genetic characteristics in the genetic makeup of one species. It includes different alleles or genetic compositions that thrive within an individual of the same species. With genetic diversity and more genetic variation, populations will have a range of traits that help them survive various environmental conditions.

Factors of Genetic Diversity

• Mutations: Mutations are spontaneous changes in an organism's DNA nucleotide sequence. They can occur due to changes or replacement of genes and chromosomes. These mutations produce new genetic variants, which change the genetic structure of a population and contribute to the overall genetic diversity of a population.
• Recombination: Genetic diversity happens due to the recombination of genetic material, and sexual reproduction plays a crucial role in maintaining genetic diversity, as it needs material from two parent organisms to produce offspring with a unique set of genes. This process of the diversity of traits within a population.
• Gene flow: Gene flow, also known as gene migration, occurs when genes transfer through populations. So this means that new generations emerge carrying a particular allele transmitted from a donor population to a recipient population. This can happen by transferring pollen, seeds, or other reproductive elements or when individuals migrate.   
• Genetic drift: Genetic drift is a random change in the frequency of alleles in a population from one generation to another over time. These random changes in allele frequencies can lead to a significant distinction in different populations. In small populations, genetic drift has a greater impact and, over time, can lead to a loss of genetic variation in a population. 
• Natural selection: Natural selection is a process where the gene pool of a population changes because of the reproduction of individuals that can resist environmental changes. It is a crucial driver of adaptation, leading to the evolution of species over time. 

Genetic Diversity Examples

Now, let’s look at some examples of genetic diversity: 

• One example of a species' genetic diversity is dogs. Different breeds of dogs within a species are selectively bred to get desired traits. Although humans control their access to a mate, we see genetic variation in different breeds of dogs. 
• Plant breeding is another example of genetic diversity. We can find different species of plants like wheat and rose flowers due to cross-breeding.
• Forest genetic resources exemplify genetic diversity with heritable materials in trees, along with woody species such as shrubs and bamboo. They hold economic, scientific, and societal value.
• A variety of medicinal plants exist as a result of interbreeding plant species. 
• Cheetahs are another example of the importance of genetic diversity. Cheetahs experienced a genetic bottleneck thousands of years ago, reducing their population to very low numbers and leading to inbreeding. 

Importance of Genetic Diversity

Why is genetic diversity important? As we know, genetic diversity refers to the inherited traits that are within a species. Genetic diversity is fundamental for the well-being and adaptability of species over time. Here are more reasons why genetic diversity is important: 

1. Adaptation to environmental changes: Different environments are subject to continuous changes. With genetic diversity, we can have different desirable traits within a population. 

This means there is a high chance that some individuals will possess characteristics that increase their adaptive potential to changing environmental conditions. 

2. Healthy population: Genetic diversity increases various physical characteristics and is vital for a healthy population. It improves a population's ability to resist diseases. 

So, if a few individuals within a population have genetic traits that make them less susceptible to some pathogens, the overall population will likely survive and reproduce.

3. Improved reproductive success: Genetic diversity helps with reproductive success, reducing the likelihood of inbreeding, where closely related individuals mate. Inbreeding can result in the expression of harmful recessive traits, which decreases the health and survival of an offspring. 
4. Resilience of species: In the face of changing environments or catastrophic events like natural disasters, species with high genetic diversity are generally more resilient. With a diverse gene pool, some individuals are more likely to have the genetic traits they need to withstand or recover from such events.   
5. Ecosystem stability: While genetic diversity is crucial for individual species, it also extends to entire ecosystems. Ecosystems with various species that have diverse genetic traits are more likely to be stable and resilient in the face of environmental pressure. 

Consequences of Low Genetic Diversity

Low genetic diversity is when there are limited alleles of genes within a species, leading to minimal differences between individuals. This often happens due to habitat loss. So, when a species’ habitat is destroyed, populations are reduced, leading to a loss of genetic diversity. 

A lack of species' genetic diversity can severely affect populations and ecosystems. Here are a few consequences of lower genetic diversity: 

1. Reduced adaptability: In the face of environmental problems like climate change, populations with limited genetic diversity may struggle to adapt. With no diverse gene pool, a limited range of potential traits will be available for natural selection to act upon.
2. Inbreeding depression: Inbreeding can be another consequence of reduced genetic diversity. Inbreeding in populations with limited genetic diversity can lead to the expression of harmful recessive traits, reducing the overall health of individuals within the population. 
3. Population decline: Genetic diversity is essential among different populations but is even more critical with small populations than large populations because the influence of genetic drift can lead to the loss of genetic diversity over time. 

So, genetic diversity is crucial for large mammals since they reproduce a few offspring. In addition, populations with low genetic diversity may experience low reproductive success, leading to a downward spiral where a shrinking population becomes increasingly vulnerable.   

Conserving Genetic Diversity

Given the critical role of genetic diversity in maintaining healthy populations and ecosystems, conservation genetics is an essential consideration for preserving and enhancing high genetic diversity. Here are some strategies to protect genetic diversity: 

Protection of habitats

Protecting natural habitats ensures that ecosystems, including diverse species and genes, can thrive. Conservationists can identify and conserve hotspots like national parks and wildlife sanctuaries to preserve the threatened species that are native to that particular habitat. 

Selective breeding programs

Captive breeding programs for endangered species strive to maintain genetic diversity. With careful breeding management, conservationists can preserve as much genetic variability as possible to avoid the negative consequences of inbreeding.  

Seed banks and cryopreservation 

Conservationists may take plant and animal species that may be threatened or hurt out of their natural habitat and take them to special settings like zoos and botanical gardens. Preserving genetic material, such as seeds or reproductive cells, in seed banks or through cryopreservation acts as a genetic insurance policy. This stored material can reintroduce genetic diversity if populations decline in the wild. 

Research and monitoring 

Conservationists can monitor populations and research their genetic diversity, gain insights into the genetic health of populations, and make informed decisions as the need arises. 

Real-life Case Studies of Genetic Diversity Conservation

Now, we will look at some real-life cases that show the importance of genetic diversity conservation:

1. Florida Panther

Attempting to increase the viability of a species by increasing genetic diversity is what we refer to as genetic rescue. The Florida panther population has significantly reduced due to habitat loss. 

Ultimately, this caused severe genetic problems like inbreeding and low genetic variation due to their small population size. Thankfully, introducing eight female Texas cougars with different genetic backgrounds helped increase genetic diversity¹ and improve the population's health.

2. Cheetahs 

Cheetahs are known for their low genetic diversity, which makes them vulnerable to diseases and environmental changes. Captive breeding programs carefully manage breeding pairs to maximize genetic variability and avoid inbreeding. 

For example, since 1956, the African cheetah has been bred in North American zoological facilities. Since then, the captive population has grown to around 200 animals due to the increased importation and captive births².

3. California Condor 

The story of the California condor begins with a massive decline in its population due to factors like habitat destruction, lead poisoning, and other threats. While these birds were a common sight in the Grand Canyon, these birds are now one of the rarest bird species in the world! 

However, it doesn't end all badly for the California Condor. In the 1980s, a captive breeding program designed to bring individuals into captivity for breeding and conservation began.

To reduce the likelihood of inbreeding and ensure genetic health, conservationists were able to manage genetic diversity within the captive population tactfully. They then gradually reintroduced the successful captive-bred individuals into the wild. As a result, the California condor population has shown signs of recovery.

4. Arabian Oryx

The Arabian oryx is a desert antelope that almost faced extinction in the wild due to habitat loss and overhunting.

Captive breeding programs were initiated in various countries, including the United Arab Emirates. As a result, conservationists reintroduced successfully bred individuals into protected reserves. The Arabian oryx population rebounded, and the species was downgraded from "Endangered" to "Vulnerable" on the IUCN Red List.

Final thoughts on genetic diversity 

As we already emphasized, genetic diversity is pivotal in species' adaptability, resilience, and long-term survival. Understanding the factors contributing to genetic diversity and its importance in our ecosystems will help effectively conserve and sustain our planet's resources.