What is genetic diversity?

Genetic diversity refers to the diversity
(or genetic variability) within species.

Each individual species possesses genes which are the source of its own unique features: In human beings, for example, the huge variety of people's faces reflects each person's genetic individuality. The term genetic diversity also covers distinct populations of a single species, such as the thousands of breeds of different dogs or the numerous variety of roses.

How do human activities affect genetic diversity?

Any change in the environment - natural or human induced causes a selection of events that only the fittest survive.

Anthropogenic impact is particularly apparent in the coastal zone and increases the number of changes occurring to individual and populations. Such pressure is exerted by

• artificial selection (harvesting, aquaculture)
• degradation of habitats (leading to a reduction of total stocks and thus increasing the likeliness of inbreeding) and
• the release of farmed fish into the wild. These activities reduce the sum of genes available, thus leaving behind a population that is less capable of tolerating any further natural or anthropogenically caused changes in environment.

These activities reduce the sum of genes available, thus leaving behind a population that is less capable of tolerating any further natural or human disturbances in environment.

What is the significance of genetic diversity?

The huge variety of different gene sets also define an individual or a whole population's ability to tolerate stress from any given environmental factor.

While some individuals might be able to tolerate an increased load of pollutants in their environment, others, carrying different genes, might suffer from infertility or even die under the exact same environmental conditions. Whilst the former will continue to live in the environment the latter will either have to leave it or die. This process is called natural selection and it leads to the loss of genetic diversity in certain habitats. However, the individuals that are no longer present might have carried genes for faster growth or for the ability to cope better with other stress factors.

Why prevent the loss of genetic diversity?

The loss of genetic diversity is difficult to see or measure. In contrast, the reduction and extinction of populations is far easier to see. Extinction is not only the loss of whole species, but is also preceded by a loss of genetic diversity within the species.

This loss reduces the species ability to perform its inherent role in the whole ecosystem.

Furthermore, the loss of genetic diversity within a species can result in the loss of useful and desirable traits (e.g. resistance to parasites). Reduced diversity may eliminate options to use untapped resources for food production, industry and medicine.