Frog mutations and genetic defects: Difference between revisions
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==Types of mutations== |
==Types of mutations== |
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Frogs and other [[amphibians]] develop different types of mutations. These physical defects can be triggered by environmental factors or by [[parasites]]. For example the [[African clawed frog]] can have many defects at birth; for example, some of African Clawed frog's grow 6 toes on their feet or the frogs can have a 5th finger that resembles a thumb.<ref name="African Clawed Frog">{{cite web | url=http://aquaticfrogs.tripod.com/id11.html | title=African Clawed Frog Mutations | accessdate=December 31, 2011}}{{Verify credibility|date=January 2012}}</ref>{{Verify credibility|date=January 2012}} When herpetologists observe mutations in frogs and their offspring they |
Frogs and other [[amphibians]] develop different types of mutations. These physical defects can be triggered by environmental factors or by [[parasites]]. For example the [[African clawed frog]] can have many defects at birth; for example, some of African Clawed frog's grow 6 toes on their feet or the frogs can have a 5th finger that resembles a thumb.<ref name="African Clawed Frog">{{cite web | url=http://aquaticfrogs.tripod.com/id11.html | title=African Clawed Frog Mutations | accessdate=December 31, 2011}}{{Verify credibility|date=January 2012}}</ref>{{Verify credibility|date=January 2012}} When herpetologists observe mutations in frogs and their offspring they suspect such mutations may arise from the frog's environment. [[Herpetologists]] then investigate for causes such as [[pesticides]] and other toxins. These mutations can be triggered by natural causes and man-made causes. |
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==''Ribeiroia ondatrae''== |
==''Ribeiroia ondatrae''== |
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Revision as of 15:54, 29 January 2012
 | This article needs additional citations for verification. (December 2011) |
Frogs are amphibians live in water as tadpoles then go through numerous bodily changes to become adults where they live on land. At times they develop mutations of the body. Some mutations and genetic defects that frogs acquire include extra limbs or misshapen legs. The first frogs with these genetic defects were found in August 1995 in south and central Minnesota.[citation needed] Herpetologists. It believed that these were not inherited defects but due to something in their environment that affected the frogs in their early lives as eggs or tadpoles.
Types of mutations
Frogs and other amphibians develop different types of mutations. These physical defects can be triggered by environmental factors or by parasites. For example the African clawed frog can have many defects at birth; for example, some of African Clawed frog's grow 6 toes on their feet or the frogs can have a 5th finger that resembles a thumb.[1][unreliable source?] When herpetologists observe mutations in frogs and their offspring they suspect such mutations may arise from the frog's environment. Herpetologists then investigate for causes such as pesticides and other toxins. These mutations can be triggered by natural causes and man-made causes.
Ribeiroia ondatrae
One natural cause for the mutations in frogs is the Ribeiroia ondatrae. Ribeiroia ondatrae is the flatworm parasite a contributor to recent increases in amphibian limb malformations, particularly missing, malformed, and extra hind legs.[2] The exact mechanism of deformation has not been determined but it has been theorized that deformation results from mechanical disruption of the cells involved in limb bud formation during the amphibian larval stage.[3] These parasites have been introduced to different areas according to the findings of Pieter Johnson, an ecologist at the University of Colorado.[4]
Environmental causes of mutation
In the past several decades, decline in amphibian populations has been occurring all over the world, for unexplained reasons which are thought to be varied but of which pesticides may be a part.[5] For example, atrazine, an organic compound commonly used as an herbicide, is known to have adverse effects on the sexual development of frogs: when exposed to even low levels of the substance, as many as 20% of frogs developed additional ovaries or testicles, or became hermaphrodites–individuals with both male and female reproductive organs. In addition, a drop in testosterone levels in male frogs due to the atrazine caused their larynges to shrink, reducing the frogs' ability to issue mating calls. These changes made it more difficult for the frogs to reproduce.[6] There is evidence of chemical pollutants causing frog developmental deformities (extra limbs, or malformed eyes).[7][8] In 1996 herpetologists discovered other reasons for these mutations were due to chemical pollution. They also discovered that frogs and other amphibians were sensitive to these chemical pollutants and pesticides were because they lived both on land and in water, making them sensitive to pollution in both of these areas. Now herpetologists believe that increased UV radiation is affecting the frogs’ eggs, which float on the surface of the water absorbing the UV rays.[9][10]
Frogs usually mutate because of environmental factors.[citation needed] Herpetologists have also discovered that frogs and other amphibians breathe through their skin, and pollution can build up in their bodies. Some herpetologists think that toxic metals and pesticides were building up in the frogs’ bodies, causing their second generation have defects in them.
Prevention
Lessening the use of pesticides and other man made factors may prevent frog mutation and genetic defects that may harm frog eggs and tadpoles. Decreasing greenhouse gas emissions may be beneficial, as well as reducing ozone depletion which is believed to negatively affect frog spawn. The world's environment benefits greatly because frogs control the insect populations on the planet Earth. If frog populations decline the world could have an insect overpopulation due to the ecological imbalance created by their absence.[11][unreliable source?]
See also
References
- ^ "African Clawed Frog Mutations". Retrieved December 31, 2011.[unreliable source?]
- ^ Dell'Amore, Christine (August 3, 2011). "Parasite Creating Deformed Frogs in Western U.S." National Geographic News. Retrieved December 30, 2011.
{{cite web}}: External link in|publisher= - ^ Dell'Amore, Christine (August 3, 2011). "Parasite Creating Deformed Frogs in Western U.S." National Geographic News. Retrieved December 30, 2011.
{{cite web}}: External link in|publisher= - ^ Dell'Amore, Christine (August 3, 2011). "Parasite Creating Deformed Frogs in Western U.S." National Geographic News. Retrieved December 30, 2011.
{{cite web}}: External link in|publisher= - ^ Cone M (December 6, 2000), A wind-borne threat to Sierra frogs: A study finds that pesticides used on farms in the San Joaquin Valley damage the nervous systems of amphibians in Yosemite and elsewhere. L.A. Times Retrieved on September 17, 2007.
- ^ Chui, Glennda (April 15, 2002). "Popular herbicide blamed for frog mutations". San Jose Mercury News. San Jose, California. Retrieved December 31, 2011.
- ^ Blaustein, Andrew R & Pieter TJ Johnson (2003). "The complexity of deformed amphibians" (PDF). Front. Ecol. Environ. 1 (2): 87–94. doi:10.1890/1540-9295(2003)001[0087:TCODA]2.0.CO;2. ISSN 1540-9295.
- ^ Burkhart, James G.; Gerald Ankley, Heidi Bell, Hillary Carpenter, Douglas Fort, David Gardiner, Henry Gardner, Robert Hale, Judy C. Helgen, Paul Jepson, Douglas Johnson, Michael Lannoo, David Lee, Joseph Lary, Rick Levey, Joseph Magner, Carol Meteyer, Michael D. Shelby, and George Lucier (2000). "Strategies for assessing the implications of malformed frogs for environmental health" (– Scholar search). Environmental Health Perspectives. 108 (1): 83–90. doi:10.2307/3454299. JSTOR 3454299. PMC 1637865. PMID 10620528.
{{cite journal}}: External link in|format= - ^ Andrew R. Blaustein, Joseph M. Kiesecker, Douglas P. Chivers and Robert G. Anthony (November 1995). "Ambient UV-B radiation causes deformities in amphibian embryos". PNAS. Vol. 92. pp. 11049–11052. doi:10.1073/pnas.92.24.11049. PMID 9391095.
{{cite news}}: CS1 maint: multiple names: authors list (link) - ^ Belden, Lisa K. (2002). "Population differences in sensitivity to UV-B radiation for larval long-toed salamanders". Ecology. Vol. 6, no. 83. pp. 1586–1590.
{{cite news}}: More than one of|author=and|last=specified (help) - ^ "Why are frog important". Retrieved December 31, 2011.[unreliable source?]
- (October 10, 1996). "Frogs give warning." Environmental Research Foundation (Peter Montague, in Rachel's Environment & Health Weekly). No. 515. Accessed December 2011.
- "Attack of the Killer Couches - Keep Toxins Out of Our Furniture!" Momsrising.org. Accessed December 2011.
- Russell, William C.; et al. (March 1990). "Corneal Lipidosis, Disseminated Xanthomatosis, and Hypercholesterolemia in Cuban Tree Frogs (Osteopilus septentrionalis)". Vol. 21, No. 1. Journal of Zoo and Wildlife Medicine. pp. 99–104. Retrieved December 30, 2011.
{{cite web}}: Explicit use of et al. in:|author=(help) - Grammer, Timothy C.; et al. (March 2005). "Identification of mutants in inbred Xenopus tropicalis". Volume 122, Issue 3. Mechanisms of Development. pp. 263–272. Retrieved December 30, 2011.
{{cite web}}: Explicit use of et al. in:|author=(help)