Genetic erosion refers to the process in which a plant or animal species faces a gradual or drastic diminishing or complete loss of its unique gene pool. A gene pool is a complete set of unique alleles that occur in the genetic matter of all members of a particular species. In genetic erosion, there is a loss of genetic diversity. This means there is a loss of particular individual genes or a loss of a certain gene combinants or gene complexes.
In the natural course of things, you do see a certain amount of loss in genetic diversity. This, however, usually concerns a few individual members, not the entire species, and so is not really a matter of concern. The genetic erosion occurring as a result of loss of natural habitat and movement restrictions imposed by human developments and activities is more alarming.
The loss of genetic diversity in this case can weaken the entire species and can lead to eventual extinction. The disappearance of certain species can have an unfavorable effect on other species that might have depended on them in some manner for their survival and ultimately on the environment as a whole.
Genetic erosion occurs in animal species for the following reasons:
- Members of the endangered species cannot meet and breed as result of habitat loss, habitat fragmentation or geographical distance.
- The individual dies without breeding.
- The individuals do breed, but because they are restricted to a certain area and cannot travel to meet different members of the species, there is low genetic diversity and inbreeding occurs. Inbreeding leads to physical defects that weaken the entire species.
Genetic erosion occurs in plant species for the following reasons:
- Loss of habitat is a cause of genetic erosion here as well.
- Overgrazing an area can lead to loss of plant species; so also the spoiling of an environment by land clearing or chemical dumping or over-zealous construction.
- Replacing local varieties of plants with those that wouldn’t occur there naturally, like plants from another area or genetically modified (GM) plants, can also lead to genetic erosion.
- Modern agriculture is also responsible to a large extent for loss of genetic diversity. Farmers tend to grow a limited number of commercial crop varieties or GM crops, enforcing a uniformity in farming, and so there has been a noticeable reduction in the many crop varieties that were seen with traditional farming.
Unless we want entire species to be wiped out, we need to take certain actions to slow down or stop the process of genetic erosion.
- Preserve natural habitats.
- Create wildlife sanctuaries and wildlife corridors that allow animals to migrate from one area to another.
- Set up breeding programs in zoos.
- In the case of critically endangered species, set up tissue and sperm banks.
- Release new members of a species in their natural habitat.
- Be careful about introducing non-native species in local areas.
- Set up seed banks.
- Cultivate wide varieties of non-GM crops.
- Guard against genetic pollution.