6.1 KiB
| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Ex situ conservation | 3/3 | https://en.wikipedia.org/wiki/Ex_situ_conservation | reference | science, encyclopedia | 2026-05-05T09:06:14.368434+00:00 | kb-cron |
=== Managing genetic disorders === Genetic disorders are often an issue within captive populations due to the fact that the populations are usually established from a small number of founders. In large, outbreeding populations, the frequencies of most deleterious alleles are relatively low, but when a population undergoes a bottleneck during the founding of a captive population, previously rare alleles may survive and increase in number. Further inbreeding within the captive population may also increase the likelihood that deleterious alleles will be expressed due to increasing homozygosity within the population. The high occurrence of genetic disorders within a captive population can threaten both the survival of the captive population and its eventual reintroduction back into the wild. If the genetic disorder is dominant, it may be possible to eliminate the disease completely in a single generation by avoiding breeding of the affected individuals. However, if the genetic disorder is recessive, it may not be possible to completely eliminate the allele due to its presence in unaffected heterozygotes. In this case, the best option is to attempt to minimize the frequency of the allele by selectively choosing mating pairs. In the process of eliminating genetic disorders, it is important to consider that when certain individuals are prevented from breeding, alleles and therefore genetic diversity are removed from the population; if these alleles are not present in other individuals, they may be lost completely. Preventing certain individuals from the breeding also reduces the effective population size, which is associated with problems such as the loss of genetic diversity and increased inbreeding.
== Examples == Showy Indian clover, Trifolium amoenum, is an example of a species that was thought to be extinct, but was rediscovered in 1993 in the form of a single plant at a site in western Sonoma County. Seeds were harvested and the species grown in ex situ facilities. The Wollemi pine is another example of a plant that is being preserved via ex situ conservation, as they are being grown in nurseries to be sold to the general public. The Orange-bellied parrot, with a wild population of 14 birds as of early February 2017, are being bred in a captive breeding program. The captive population consists of around 300 birds.
== Drawbacks ==
Ex situ conservation, while helpful in humankind's efforts to sustain and protect our environment, is rarely enough to save a species from extinction. It is to be used as a last resort, or as a supplement to in situ conservation because it cannot recreate the habitat as a whole: the entire genetic variation of a species, its symbiotic counterparts, or those elements which, over time, might help a species adapt to its changing surroundings. Instead, ex situ conservation removes the species from its natural ecological contexts, preserving it under semi-isolated conditions whereby natural evolution and adaptation processes are either temporarily halted or altered by introducing the specimen to an unnatural habitat. In the case of cryogenic storage methods, the preserved specimen's adaptation processes are (quite literally) frozen altogether. The downside to this is that, when re-released, the species may lack the genetic adaptations and mutations which would allow it to thrive in its ever-changing natural habitat. Furthermore, ex situ conservation techniques are often costly, with cryogenic storage being economically infeasible in most cases since species stored in this manner cannot provide a profit but instead slowly drain the financial resources of the government or organization determined to operate them. Seedbanks are ineffective for certain plant genera with recalcitrant seeds that do not remain fertile for long periods of time. Diseases and pests foreign to the species, to which the species has no natural defense, may also cripple crops of protected plants in ex situ plantations and in animals living in ex situ breeding grounds. These factors, combined with the specific environmental needs of many species, some of which are nearly impossible to recreate by man, make ex situ conservation impossible for a great number of the world's endangered flora and fauna.
== See also ==
== References ==
== Further reading == Engels, J.M.M.; L. Visser, eds. (2003). A Guide to Effective Management of Germplasm Collections. CABI, IFPRI, IPGRI, SGRP. Archived from the original on 25 May 2007. 174 p. FAO. (2007). The Global Plan of Action for Animal Genetic Resources and the Interlaken Declaration. Rome. FAO. (2015). The Second Report on the State of the World's Animal Genetic Resources for Food and Agriculture. Archived 18 September 2018 at the Wayback Machine Rome. Guerrant, Edward O.; Havens, Kayri; Maunder, Mike, eds. (2004). Ex situ plant conservation: supporting species survival in the wild. Island Press. Kameswara, N.; J. Hanson; M. E. Dulloo; K. Ghosh; A. Nowell; M. Larinde. Manual of Seed Handling in Genebanks. Bioversity International, CTA (Technical Center for Agricultural and Rural Cooperation), FAO, ILRI. Archived from the original on 21 January 2008. 147 p. Koo, B.; Pardey, P. G.; Wright, B. D.; et al. (2004). Saving Seeds. CABI, IFPRI, IPGRI, SGRP. Archived from the original on 11 December 2008.
== External links == Cloning to revive extinct species, May 28, 2002, Grant Holloway, CNN Reproductive Technologies and Conservation of Endangered Cats Louisiana's frozen ark ONLINE BOOK: In situ conservation of livestock and poultry, 1992, Food and Agriculture Organization of the United Nations and the United Nations Environment Programme "The Challenges of Ex situ Orchid Conservation", Orchid Conservation Coalition Botanic Gardens Conservation International – international organisation supporting ex situ conservation of priority plant species Domestic Animal Diversity Information System Implementing the Global Plan of Action for Animal Genetic Resources