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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Genetic pollution | 2/3 | https://en.wikipedia.org/wiki/Genetic_pollution | reference | science, encyclopedia | 2026-05-05T07:18:16.461995+00:00 | kb-cron |
=== Domestic populations === Increased contact between wild and domesticated populations of organisms can lead to reproductive interactions that are detrimental to the wild population's ability to survive. A wild population is one that lives in natural areas and is not regularly looked after by humans. This contrasts with domesticated populations that live in human controlled areas and are regularly, and historically, in contact with humans. Genes from domesticated populations are added to wild populations as a result of reproduction. In many crop populations this can be the result of pollen traveling from farmed crops to neighboring wild plants of the same species. For farmed animals, this reproduction may happen as the result of escaped or released animals. A popular example of this phenomenon is the gene flow between wolves and domesticated dogs. The New York Times cites, from the words of biologist Luigi Boitani, "Although wolves and dogs have always lived in close contact in Italy and have presumably mated in the past, the newly worrisome element, in Dr. Boitani's opinion, is the increasing disparity in numbers, which suggests that interbreeding will become fairly common. As a result, 'genetic pollution of the wolf gene pool might reach irreversible levels', he warned. 'By hybridization, dogs can easily absorb the wolf genes and destroy the wolf, as it is,' he said. The wolf might survive as a more doglike animal, better adapted to living close to people, he said, but it would not be 'what we today call a wolf.'"
==== Aquaculture ==== Aquaculture is the practice of farming aquatic animals or plants for the purpose of consumption. This practice is becoming increasingly common for the production of salmon. This is specifically termed aquaculture of salmonids. One of the dangers of this practice is the possibility of domesticated salmon breaking free from their containment. The occurrence of escaping incidents is becoming increasingly common as aquaculture gains popularity. Farming structures may be ineffective at holding the vast number of fast growing animals they house. Natural disasters, high tides, and other environmental occurrences can also trigger aquatic animal escapes. The reason these escapes are considered dangers is the impact they pose for the wild population they reproduce with after escaping. In many instances the wild population experiences a decreased likelihood of survival after reproducing with domesticated populations of salmon. The Washington Department of Fish and Wildlife cites that "commonly expressed concerns surrounding escaped Atlantic salmon include competition with native salmon, predation, disease transfer, hybridization, and colonization." A report done by that organization in 1999 did not find that escaped salmon posed a significant risk to wild populations.
==== Crops ==== Crops refer to groups of plants grown for consumption. Despite domestication over many years, these plants are not so far removed from their wild relatives that they couldn't reproduce if brought together. Many crops are still grown in the areas they originated and gene flow between crops and wild relatives impacts the evolution of wild populations. Farmers can avoid reproduction between the different populations by timing their planting of crops so that crops are not flowering when wild relatives would be. Domesticated crops have been changed through artificial selection and genetic engineering. The genetic make-ups of many crops is different from those of their wild relatives, but the closer they grow to one another the more likely they are to share genes through pollen. Gene flow persists between crops and wild counterparts.
=== Genetically engineered organisms ===
Genetically engineered organisms are genetically modified in a laboratory, and therefore distinct from those that were bred through artificial selection. In the fields of agriculture, agroforestry and animal husbandry, genetic pollution is being used to describe gene flows between GE species and wild relatives. An early use of the term "genetic pollution" in this later sense appears in a wide-ranging review of the potential ecological effects of genetic engineering in The Ecologist magazine in July 1989. It was also popularized by environmentalist Jeremy Rifkin in his 1998 book The Biotech Century. While intentional crossbreeding between two genetically distinct varieties is described as hybridization with the subsequent introgression of genes, Rifkin, who had played a leading role in the ethical debate for over a decade before, used genetic pollution to describe what he considered to be problems that might occur due to the unintentional process of (modernly) genetically modified organisms (GMOs) dispersing their genes into the natural environment by breeding with wild plants or animals. Concerns about negative consequences from gene flow between genetically engineered organisms and wild populations are valid. Most corn and soybean crops grown in the midwestern USA are genetically modified. There are corn and soybean varieties that are resistant to herbicides like glyphosate and corn that produces neonicotinoid pesticide within all of its tissues. These genetic modifications are meant to increase yields of crops but there is little evidence that yields actually increase. While scientists are concerned genetically engineered organisms can have negative effects on surrounding plant and animal communities, the risk of gene flow between genetically engineered organisms and wild populations is yet another concern. Many farmed crops may be weed resistant and reproduce with wild relatives. More research is necessary to understand how much gene flow between genetically engineered crops and wild populations occurs, and the impacts of genetic mixing.
==== Mutated organisms ==== Mutations within organisms can be executed through the process of exposing the organism to chemicals or radiation in order to generate mutations. This has been done in plants in order to create mutants that have a desired trait. These mutants can then be bred with other mutants or individuals that are not mutated in order to maintain the mutant trait. However, similar to the risks associated with introducing individuals to a certain environment, the variation created by mutated individuals could have a negative impact on native populations as well.