Genetic erosion is a process whereby an already limited gene pool of an endangered species of plant or animal diminishes even more when individuals from the surviving population die off without getting a chance to meet and breed with others in their endangered low population (see: Small population size). In Population genetics, a gene pool is the complete set of unique Alleles in a Species or Population. An endangered species is a population of an organism which is at risk of becoming Extinct because it is either few in numbers or threatened by changing environmental or predation Populations with small population size behave differently to larger populations
Genetic erosion occurs because each individual organism has many unique genes which get lost when it dies without getting a chance to breed. Low genetic diversity in a population of wild animals and plants leads to a further diminishing gene pool, inbreeding and a weakening immune system and fast tracks that species towards eventual extinction. In Biology and Ecology, extinction is the cessation of existence of a Species or group of taxa.
All the world's endangered species are plagued by varying degrees of Genetic Erosion and most need a human assisted breeding program to keep their population viable and to keep them from going extinct in the long run. The more critically endangered the specie is the more magnified the effect of genetic erosion gets when each surviving individual of the species is lost without getting a fair chance to breed. Organisms with a conservation status of critically endangered have an extremely high risk of becoming extinct
Genetic erosion gets compounded and accelerated by habitat fragmentation, today most endangered species live in smaller and smaller chunks of fragmented habitat interspersed with human settlements and farmland making it impossible for them to naturally meet and breed with others of their kind, many die off without getting a fair chance to breed and pass on their genes in the living population. Habitat fragmentation is a process of environmental change important in Evolution and Conservation biology. A habitat (which is Latin for "it inhabits" is an Ecological or environmental area that is inhabited by a particular Species.
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. In Population genetics, a gene pool is the complete set of unique Alleles in a Species or Population. In Biology, a species is one of the basic units of Biological classification and a Taxonomic rank. In Biology a population is the collection of inter-breeding organisms of a particular Species; in Sociology An allele (ˈæliːl (UK /əˈliːl/ (US (from the Greek αλληλος allelos, meaning each other) is one member of a pair or series of different forms A large gene pool indicates extensive genetic diversity, which is associated with robust populations that can survive bouts of intense selection. Genetic diversity is a level of Biodiversity that refers to the total number of genetic characteristics in the genetic makeup of a species In the context of Evolution, certain traits or Alleles of a Species may be subject to selection Meanwhile, low genetic diversity (see inbreeding and population bottlenecks) can cause reduced biological fitness and an increased chance of extinction. Inbreeding is breeding between close Relatives whether plant or animal A population bottleneck (or genetic bottleneck) is an Evolutionary event in which a significant percentage of a population or species is killed or otherwise prevented Fitness (often denoted w in Population genetics models is a central concept in evolutionary theory. In Biology and Ecology, extinction is the cessation of existence of a Species or group of taxa.
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Processes and consequences
“A population bottleneck creates a shrinking gene pool that leaves fewer and fewer mating partners. What are the genetic implications? The animals become part of a high stakes poker game -- with a crooked dealer. After beginning with a 52-card deck, the players wind up with, say, five cards that they are dealt over and over. As they begin to inbreed, congenital effects appear, both physical and reproductive. Often abnormal sperm increase; infertility rises; the birthrate falls. Most perilous in the long run, each animal's immune defense system is weakened. Thus, even if an endangered species in a bottleneck can withstand whatever human development may be eating away at its habitat, it still faces the threat of an epidemic that could well be fatal to the entire population. “[1]
Genetic erosion in agricultural and livestock biodiversity
- See also: Agricultural biodiversity
Genetic erosion in agricultural and livestock biodiversity is the loss of genetic diversity, including the loss of individual genes, and the loss of particular combinants of genes (or gene complexes) such as those manifested in locally adapted landraces of domesticated animals or plants adapted to the natural environment in which they originated. Agricultural biodiversity is a sub-set of general Biodiversity including all cultivated varieties Agriculture refers to the production of goods through the growing of plants and fungi and the raising of domesticated Animals The study of agriculture Livestock is the term used to refer (singularly or plurally to a Domesticated Animal intentionally reared in an agricultural setting to produce such as Food Landrace refers to domesticated animals or plants adapted to the natural and cultural environment in which they live (or originated and in some cases work they often develop Domestication (from Latin domesticus) refers to the process whereby a Population of Animals The term genetic erosion is sometimes used in a narrow sense, such as for the loss of alleles or genes, as well as more broadly, referring to the loss of varieties or even species. The major driving forces behind genetic erosion in crops are: variety replacement, land clearing, overexploitation of species, population pressure, environmental degradation, overgrazing, policy and changing agricultural systems.
The main factor, however, is the replacement of local varieties of domestic plants and animals by high yielding or exotic varieties or species. A large number of varieties can also often be dramatically reduced when commercial varieties (including GMOs) are introduced into traditional farming systems. This article is about organisms which have been genetically modified Many researchers believe that the main problem related to agro-ecosystem management is the general tendency towards genetic and ecological uniformity imposed by the development of modern agriculture.
Human intervention, modern science and safeguards to guard against genetic erosion
In-situ conservation
With advances in modern science several techniques and safeguards have emerged to check the relentless advance of genetic erosion and the resulting acceleration of endangered species towards extinction. In-situ conservation means "on-site conservation " It is the process of protecting an endangered Plant or Animal Species However many of these techniques and safeguards are too expensive yet to be practical, the best way to protect species is to protect their habitat and to let them live in it naturally. A habitat (which is Latin for "it inhabits" is an Ecological or environmental area that is inhabited by a particular Species.
Wildlife sanctuaries and national parks have been created to preserve entire ecosystems with all the web of species which call them home. A wildlife refuge, also called a wildlife sanctuary, may be a naturally-occurring sanctuary such as an Island, that provides protection for Species from A national park is a reserve of land usually declared and owned by a national Government, protected from most Human development and pollution An ecosystem is a natural unit consisting of all plants animals and micro-organisms( Biotic factors in an area functioning together with all of the non-living physical ( Wildlife corridors are created to join fragmented habitats (see Habitat fragmentation) to enable endangered species to travel, meet and breed with others of their kind. A wildlife corridor or green corridor is a strip of habitat connecting wildlife populations separated by human activities (such as roads development or logging Habitat fragmentation is a process of environmental change important in Evolution and Conservation biology. Scientific conservation and modern wildlife management techniques with the help of scientifically trained staff help manage these protected ecosystems and the wildlife found in them. "Conservation Biology" redirects here For the Scientific journal, see Conservation Biology (journal. Wildlife management is the process of keeping certain Wildlife populations including endangered animals at desirable levels determined by wildlife managers Wild animals are also translocated and reintroduced to other locations physically when fragmented wildlife habitat is too far and isolated to be able to link it with a wildlife corridor or when local extinction has already occurred. Reintroduction is the deliberate release of species into the wild from captivity or relocated from other areas where the species survives
Ex-situ conservation
Modern policies of the zoo associations and zoos around the world have changed to putting extreme importance on keeping and breeding wild sourced pure species and subspecies of animals and birds in their registered endangered species breeding programs which will have a chance to be reintroduced and survive in the wild. Ex-situ conservation means literally "off-site conservation " This is a partial list of Zoo and Aquaria associations: Global World Association of Zoos and Aquariums (WAZA A zoological garden, shortened to zoo, is an institution in which living animals are exhibited in captivity In Biology, a species is one of the basic units of Biological classification and a Taxonomic rank. In Zoology, as in other branches of Biology, subspecies is the Taxonomic rank immediately subordinate to a Species. Main objectives of zoos today has changed to breed pure breed species and subspecies to assist conservation efforts in the wild. Zoos do this by maintaining extremely detailed scientific breeding records i. e. studbooks and loaning their pure breed wild animals and birds to other zoos around the country and indeed globally for breeding to safeguard against inbreeding and hybrids which are considered genetically compromised thus not fit for reintroduction in the wild and in the case of unnaturally found hybrids also to guard against genetic pollution in naturally evolved, region specific, pure wild stocks. A breed registry, also known as a stud book or register, in Animal husbandry and the Hobby of Animal fancy, is an official list of Inbreeding is breeding between close Relatives whether plant or animal In Biology, hybrid has two meanings The first meaning is the result of interbreeding between two animals or plants of different taxa. Genetic pollution is undesirable Gene flow into wild populations
Costly and sometimes controversial ultra modern Ex-situ conservation techniques have emerged for saving the genetic biodiversity on our planet and the diversity in their gene pool by guarding against Genetic erosion through modern concepts like seedbanks, sperm banks, tissue banks, etc. Ex-situ conservation means literally "off-site conservation " Biodiversity is the variation of Life forms within a given Ecosystem, Biome or for the entire Earth. In Population genetics, a gene pool is the complete set of unique Alleles in a Species or Population. A seedbank stores Seeds as a source for planting in case seed reserves elsewhere are destroyed A sperm bank or cryobank is a facility that collects and stores human sperm mainly from sperm donors primarily for the purpose of achieving pregnancies Genetic diversity, DNA, Sperms, eggs, embryos can now be frozen and kept in special banks and laboratories which are sometimes called Modern Noha's Ark or Frozen Zoos where modern cryopreservation techniques are used to freeze these living materials and yet keep them alive by storing them submerged in liquid nitrogen tanks. Genetic diversity is a level of Biodiversity that refers to the total number of genetic characteristics in the genetic makeup of a species Deoxyribonucleic acid ( DNA) is a Nucleic acid that contains the genetic instructions used in the development and functioning of all known A spermatozoon or spermatozoan ( pl spermatozoa) from the Ancient Greek σπέρμα (seed and ζῷον (living being and more commonly known An embryo (from Greek:, plural, lit "that which grows" from en- "in" + bryein "to swell be full" is a multicellular A laboratory (informally lab) is a facility that provides controlled conditions in which scientific Research, Experiments and A frozen zoo is a Cryogenic facility for the long term storage of animal and plant genetic material such as DNA, Sperm, eggs, and Embryos Cryopreservation is a process where cells or whole tissues are preserved by cooling to low sub-zero Temperatures such as (typically 77 K or −196 Liquid nitrogen (liquid density at the Triple point is 0707 g/mL is the liquid produced industrially in large quantities by Fractional distillation of Thus preserved material can then be used for Artificial insemination, in vitro fertilization, embryo transfer and cloning etc. AIH redirects here For the indie rock band abbreviated AIH see Architecture in Helsinki Artificial insemination (AI is the process by which In vitro fertilisation ( IVF) is a process by which Embryo transfer refers to a step in the process of in vitro fertilization (IVF whereby one or several Embryos are placed into the Uterus Cloning in Biology is the process of producing populations of genetically-identical individuals that occurs in nature when organisms such as Bacteria, Insects to protect diversity in the gene pool of critically endangered species.
It is today possible to save Endangered species from Extinction by preserving parts like tissue, sperms, eggs etc. An endangered species is a population of an organism which is at risk of becoming Extinct because it is either few in numbers or threatened by changing environmental or predation In Biology and Ecology, extinction is the cessation of existence of a Species or group of taxa. even after the death of a critically endangered animal or collected from one found freshly dead in captivity or from wild and resurrect it with the help of cloning and give it another chance to breed its genes into the living population of the respective species which is threatened with extinction. Resurrection of dead critically endangered wildlife with the help of cloning is still being perfected and is still too expensive to be practical but with time and advancement is science it may well become a routine procedure in the near future. However Modern Noha's Ark or Frozen Zoos and the use of modern cryopreservation techniques makes lot of sense to preserve living material cheaply which future generations of mankind may well use to diversify limited gene pools of endangered species.
See also
- Biodiversity
- Biome
- Conservation biology
- Ex-situ conservation
- Frozen zoo
- Genetics
- Genetic pollution
- In-situ conservation
- Population genetics
- Small population size
References
- ^ “A population bottleneck creates a shrinking gene pool that leaves fewer and fewer mating partners. What are the genetic implications? The animals become part of a high stakes poker game -- with a crooked dealer. After beginning with a 52-card deck, the players wind up with, say, five cards that they are dealt over and over. As they begin to inbreed, congenital effects appear, both physical and reproductive. Often abnormal sperm increase; infertility rises; the birthrate falls. Most perilous in the long run, each animal's immune defense system is weakened. Thus, even if an endangered species in a bottleneck can withstand whatever human development may be eating away at its habitat, it still faces the threat of an epidemic that could well be fatal to the entire population.” SOURCE: “GENETIC EROSION A Global Dilemma” by Stephen J. O'Brien; Chief, Laboaratory of Viral Carcinogenesis, National Cancer Institute; National Geographic, April 1992, page 136; Accessed on October 20, 2007; Posted online by Oslo Cyclotron Laboratory at the Department of Physics, UiO; The University of Oslo in Norway
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