Genetic Pollution: Unraveling The Causes Of Gene Alteration

Genetic pollution is defined as the introduction of foreign or modified genes by human beings into a wild genome, causing undesirable gene flow from domestic, feral, and non-native species into wild indigenous species. It is often associated with the release of genetically modified organisms (GMOs) into the environment, which can have various effects on plants, animals, and the environment. Opponents of GMOs argue that they can poison the soil and cause genetic pollution, leading to the spread of antibiotic-resistant genes and compromising healthcare. In plants, genetic pollution can occur through cross-pollination, animal pollination, or water pollination, resulting in changes to the genetic makeup of the receiving plants. In animals, genetic pollution is less common, but it can occur through the breeding of farmed and wild species, potentially altering their genetic characteristics and even leading to extinction. The term pollution in genetic pollution conveys the negative impact of mixing genetic information, although the outcomes of such mixing can vary.

Genetically modified organisms (GMOs)

One of the primary concerns surrounding GMOs is their potential to cause genetic pollution. Genetic pollution occurs when the genes from genetically modified organisms are dispersed into natural organisms, particularly through cross-pollination. This can lead to the introduction of unwanted genetic material, negatively impacting the fitness of a population. For example, the spread of herbicide-resistant genes from GMO crops to weeds can result in the emergence of "superweeds" that are challenging to control. Similarly, the transfer of antibiotic-resistant genes to gut flora and soil bacteria can compromise healthcare and cause ecological imbalances.

The use of GMO crops has been linked to a decline in biodiversity. For instance, the expansion of herbicide-tolerant GMO corn and soy has contributed to the destruction of the monarch butterfly's habitat in North America. The increased use of herbicides, such as glyphosate, to manage these crops has been detrimental to the butterfly's food sources. Additionally, the introduction of GMO insect-resistant crops has led to the development of "superpests," as some insects have become resistant to the toxins in these crops.

While GMO crops offer benefits such as increased crop yields, reduced costs for food production, and enhanced nutritional content, there are valid concerns about their potential risks. The unpredictable nature of genetic modification can lead to unintended consequences, as highlighted by environmentalists. The debate around the commercialisation and use of GMOs is ongoing, with health authorities conducting ongoing research to assess their long-term safety and environmental impact.

Genetically engineered organisms

Genetic pollution is defined as the uncontrolled dispersal of contaminated altered genes from GEOs to natural organisms, particularly through cross-pollination. It occurs when there is an introduction of a species that is not native to a particular environment, and GEOs are examples of individuals that could cause genetic pollution following their introduction. This introduction can be either intentional or accidental.

The term "genetic pollution" is often used by conservation biologists and conservationists to describe undesirable gene flow from domestic, feral, and non-native species into wild indigenous species. This can lead to outbreeding depression, the introduction of unwanted phenotypes, and potentially, extinction. For example, the introduction of the Asian Longhorned beetle in North America is believed to have been through cargo at trade ports, and these beetles are now estimated to pose a risk to 35% of urban trees.

In agriculture, agroforestry, and animal husbandry, genetic pollution is associated with gene flows between GE species and their wild relatives. The potential ecological effects of this were discussed in a 1989 issue of The Ecologist magazine, and the term was later popularized by environmentalist Jeremy Rifkin in his 1998 book, *The Biotech Century*.

There are valid concerns about the negative consequences of gene flow between GEOs and wild populations. For instance, the escape of a foreign gene through pollen or seed dispersal can create super weeds or cause genetic pollution among other crops. However, it is important to note that not all GEOs cause genetic pollution, and studies have been conducted to assess the risks associated with GEOs. In a 10-year study of four different crops, none of the genetically engineered plants were found to be more invasive or persistent than their conventional counterparts.

Non-native species

Genetic pollution is defined as ""the dispersal of contaminated altered genes from genetically engineered organisms to natural organisms, especially by cross-pollination". It is related to the population genetics concept of gene flow, which occurs when genetic material is unintentionally introduced to a population. This can happen when a non-native species is brought into a new ecosystem, either intentionally or accidentally, and can have both positive and negative effects on the population.

Invasive species can invade both large and small native populations and have a profound effect. They can hybridize with native species, causing genetic pollution and altering the genetic pool irreversibly. For example, in the Netherlands, a native crested newt species experienced genetic pollution through hybridization with an invasive congener. In another example, ibex were introduced from Turkey and Sinai to Czechoslovakia to promote the ibex population there, but the introduced ibex produced offspring too early, causing the overall population to disappear completely.

To prevent and manage genetic pollution from non-native species, organizations like TRAFFIC, the international wildlife trade monitoring network, work to limit the trade in wild plants and animals so that it does not threaten conservationist goals. Additionally, studies have been conducted to assess the risks of genetic pollution associated with non-native, genetically engineered organisms.

Hybridization

One notable example of hybridization leading to genetic pollution is the case of ibex in Czechoslovakia. Ibex from Turkey and Sinai were introduced to boost the local ibex population. However, the hybrid offspring were ill-adapted to their new environment, leading to the eventual disappearance of the entire population. This illustrates the potential consequences of hybridization, where the introduction of new genetic material can disrupt the delicate balance of an ecosystem.

In the field of agriculture, agroforestry, and animal husbandry, genetic pollution is often associated with gene flow between genetically engineered (GE) or genetically modified (GMO) species and their wild relatives. This can occur through cross-pollination or breeding, resulting in the unintentional dispersal of modified genes into natural populations. For instance, studies have identified transgenes from GE maize in landraces of maize in Oaxaca, Mexico, indicating potential genetic pollution.

Furthermore, hybridization between threatened native species and invasive species can result in genetic pollution, as observed in the case of the native crested newt species, Triturus cristatus, in the Netherlands. Molecular studies revealed that the invasive Triturus carnifex had displaced the native species through hybridization, posing a significant conservation challenge.

Environmental concerns

Genetic pollution can occur through the introduction of a non-native species to a particular environment, including genetically engineered organisms. The potential risks associated with genetically engineered organisms have been widely debated, with opponents arguing that they can poison the soil and cause "genetic" pollution, resulting in the spread of antibiotic-resistant genes that could compromise healthcare. Proponents, on the other hand, highlight the potential benefits of increased resistance to pathogens and reduced mycotoxin contamination caused by fungi.

In agriculture, agroforestry, and animal husbandry, genetic pollution refers to gene flows between genetically engineered species and their wild relatives. This can lead to the creation of "super weeds" that are resistant to herbicides and pests, impacting farmland biodiversity and food chains. An example of this is the discovery of transgenes from GE maize in landraces of maize in Oaxaca, Mexico.

The introduction of new species can also lead to hybridization with native species, causing genetic pollution and potentially leading to the disappearance of the original population. An example of this is the introduction of ibex from Turkey and Sinai to Czechoslovakia to promote the ibex population, which resulted in hybrids that produced offspring too early, causing the overall population to disappear.

Natural disasters, high tides, and other environmental occurrences can trigger aquatic animal escapes, which can impact wild populations through competition, predation, disease transfer, hybridization, and colonization. While some introduced species may have positive effects on an environment, such as the correlation between invasive honeysuckle plants and bird diversity in Pennsylvania, the overall consensus is that the introduction of invasive species is highly context-dependent and can have detrimental and irreversible effects on native populations.

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