Genetic pollution happens when pure genes /
gene pool of wild animals and plants become hybridized (see
hybrid) with
domesticated varieties or with the genes of other subspecies from far away regions which would not have happened naturally. Genetic pollution usually happens as a result and a consequence of short-sighted actions of man.
Nowadays, with several domesticated and hybridized animals and plants living in and all around forests which still hold pure wild ancestor species and subspecies of their kind, Genetic Pollution has become a major threat to pure wild populations and their natural genetic makeup. Purebred wild populations of animals and plants have evolved naturally over millions of years through a process of
Natural selection and are most adaptable to living in the particular regions of earth where they exist presently. They have scientifically the most endurable and viable genetic makeup to live where they live. Genetic pollution leads to hybridized animals and plants which, though they may look exactly the same, are not as strong as their pure wild ancestors to survive naturally for long; they also have low immunity to diseases.
Widespread genetic pollution leads to quicker
extinction of wild animals and plants.
In modern times national and international
zoo associations have realized how important it is to maintain purebred animals which may have a chance to be reintroduced and survive in the wild. It has become mandatory for
Zoos to maintain detailed breeding records of their wild animal stock and keep
Studbooks. Random hybridization of wild animals with subspecies from different regions was a common practice which plagued all of world's zoos until recently.
Scientists today desperately want to conserve the pure wild gene stock and genetic makeup of wild animals and wild plants. They are considered to be a valuable source of strong genes which can in the future be used to hybridize domesticated varieties, to make them stronger and more resistant to climate and diseases, thus leading to an improvement in food stocks for humans.
The
gene pool of a
species or a
population is the complete set of unique
alleles that would be found by inspecting the genetic material of every living member of that species or population. A large gene pool indicates extensive
genetic diversity, which is associated with robust populations that can survive bouts of intense
selection. Meanwhile, low genetic diversity (see
inbreeding and
population bottlenecks) can cause reduced
biological fitness and an increased chance of
extinction.
Examples of Genetic Pollution
- Captive Asiatic Lions in zoos till recently in India were genetically polluted with genes of Circus confiscated African Lions which had been randomly hybridized with them.
- Wild Jungle fowl in India and South Asia are the ancestor of all Poultry Chickens. These are thought to be facing a serious threat of extinction because of genetic pollution which is occurring at the edge of forests where domesticated free ranging chickens are commonly kept in bordering villages and towns.
- Wild Asiatic Water Buffalo are threatened by genetic pollution when they come into contact with common domesticated water buffalo which live in and around forests. The domesticated animals daily come to graze within forests which have been designated as Wildlife Sanctuaries and National Parks for their wild ancestors.
- Many herds of surviving American Bison, even though they look exactly the same, were hybridized with genes of beef cattle by landowners in a short-sighted effort to improve their meat quality (see Cattalo), leading to widespread genetic pollution in the surviving bisons in America.
- Wild varieties of Bananas are genetically polluted by cross pollination with domesticated varieties being grown in farms, towns and villages threatening the pure wild stock with extinction.
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