Living organisms have a unique code that forms their bodies, known as DNA (Deoxyribonucleic Acid). DNA is a molecule that carries all the instructions needed by all organisms throughout their life cycles. Naturally, the genetic information contained in DNA is passed down from parents to the next generation through reproduction.

Biological variation at the DNA-level forms the basis for all biodiversity (Photo Credit : Jerker Lokrantz/Azote)

Each individual's DNA has a different and unique arrangement, even within the same species. This diversity in DNA structure is called genetic diversity. Genetic diversity influences many factors, such as physical appearance, skin color, eye color, hair, and even nail shape, among others. This genetic diversity is crucial because it is closely related to better survival abilities.

Genetic Diversity as a Factor in Species Survival

Large populations can harbour much genetic diversity, small populations can not do that and will rapidly loose variation (Photo Credit : Jerker Lokrantz/Azote)

Species with significant DNA differences are said to have high genetic diversity. In species with high genetic diversity, there are many DNA mutations that cause differences in important traits. These differences are essential because high genetic diversity can help a species adapt to environmental changes. On the other hand, low genetic diversity, often resulting from inbreeding, can be a major factor in species extinction. Here are some reasons why low genetic diversity can lead to extinction:

1. Limited Adaptation to Environmental Changes:

   Species with low genetic diversity have limited adaptive abilities to environmental changes. When the environment changes, for example, due to climate change or habitat loss, these species may lack the necessary genetic variation to survive.

2. Limited Natural Selection:

   In populations with low genetic diversity, natural selection has fewer variations to work with, reducing the chances of developing traits that can help the species survive under changing conditions.

3. Reproductive Challenges:

   Low genetic diversity can cause reproductive issues, such as infertility or genetic abnormalities, which can reduce the number of healthy offspring.

4. Vulnerability to Disease:

   Low genetic diversity also makes species more vulnerable to diseases. Without sufficient genetic variation, an entire population could be threatened by a single type of disease that can spread quickly.

Some examples of population decline leading to species being on the brink of extinction due to low genetic diversity caused by inbreeding include:

1. Javan Rhino and Sumatran Rhino
2. Cheetah
3. Isle Royale Wolves
4. Kakapo (a flightless parrot from New Zealand)
5. Vaquita (a porpoise native to the Gulf of California)

The above species are on the verge of extinction, with only a few individuals remaining. Conservation efforts are focused on increasing genetic diversity through controlled breeding programs and habitat protection to ensure the survival of these species.

-YN