Gene Bank
Biological diversity occurs at three different levels, Ecosystem diversity, Species diversity, Genetic diversity.
Genetic diversity gives species the ability to adapt to changing environments, including pests, diseases, and climate change. It is very important to conserve these valuable genetic resources so that these can available for use and study in the future. There are two main approaches to maintaining genetic diversity: in-situ conservation and ex-situ conservation. in-situ conservation is concerned with maintaining species within their natural environments. Ex situ conservation comprises of methods that maintain the genetic integrity of collected germplasm samples outside their natural habitats. Genetic resources that are maintained
outside of their natural habitats and managed under artificial conditions in facilities are known as gene banks.
Gene bank is a type of biorepository where genetic material is collected, stored, catalogued and made available for redistribution. Local crop varieties, known as "landraces", are the result of generations of careful farmer selection. Due to a combination of environmental and social changes in farming communities, intensification of cultivation of a particular high yielding crop globally and inbreeding in small populations, large numbers of local crop varieties are disappearing at an alarming rate, which cause rapid decline in genetic diversity.
Conserving the genetic diversity of our crops, landraces and related wild species is essential to ensure future plant breeders can access this variation, especially in view of increased food demand by a growing world population and climate change. Genebank play an important role in the conservation, availability and use of a wide range of plant genetic diversity for crop improvement for food and nutrition security. They help bridge the past and the future by ensuring the continued availability of genetic resources for research, breeding and improved seed delivery for a sustainable and resilient agricultural system.
Gene banks also preserve cells or organisms that host unusual gene variants- genes with special traits. Those genes might later prove useful when some disease epidemic strikes, when the climate changes or when other factors threaten the survival of plants or animals. Farmers could use the banked deposits stored cells or tissues to restore genetic diversity or to introduce traits from other breeds or varieties.
For plants, this could be achieved by freezing cuttings from the plant, or stocking
the seeds (eg. in seedbanks). For animals, this could be done by freezing of sperm
and eggs until further need. With corals, fragments are taken which are stored in
water tanks under controlled condition.
Plant genetic material in a 'gene bank' is preserved at -196°C in Liquid Nitrogen as mature seed (dry).
In plants, it is possible to unfreeze the material and propagate it, however, in animals, a living female is required for artificial insemination.
A gene bank can hold many different types of materials. There may be seeds that will grow into whole plants or eggs and sperm that can be united to create an animal. There may be animal embryos, which can be implanted into surrogate mothers. Some gene banks store stem cells, which scientists may one day use to produce eggs and sperm. Banks can even store reproductive organa, such as ovaries and testes. After thawing, these organs can grow into animals of other breeds or even other species. Later, when mature, these organs will produce spent or eggs with the genes of the animal from which they had been harvested. In animals, it is not possible to create a whole organism through stored genetic material directly but it can be created by artificial insemination after In Vitro Fertilization of stored eggs and sperms
In an effort to conserve agricultural biodiversity, gene banks are used to store and conserve the plant genetic resources of major crop plants and their crop wildrelatives.
Difficulties
Gene banks use low temperatures to stop chemical and biological activity that might break down cells. Freezing and thawing cells has to be done quickly and carefully so that the material will still be viable after it has warmed back up. But some plant and animal materials which are not resilient require extra special care.
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