Somaclonal variation can be obtained by
application of colchicine
irradiation with gamma rays
tissue culture
hybridisation.
C.
tissue culture
Somaclonal variation is the variation seen in plants that have been produced by plant tissue culture. Chromosomal rearrangements are an important source of this variation. Somaclonal variation is not restricted to, but is particularly common in, plants regenerated from callus. The variations can be genotypic or phenotypic, which in the latter case can be either genetic or epigenetic in origin.
Tissue culture, a method of biological research in which fragments of tissue from an animal or plant are transferred to an artificial environment in which they can continue to survive and function. The cultured tissue may consist of a single cell, a population of cells, or a whole or part of an organ. Cells in culture may multiply; change size, form, or function; exhibit specialized activity (muscle cells, for example, may contract); or interact with other cells.
In India, we find mangoes with different flavours, colours, fibre content, sugar content and even shelf-life. The large variation is on account of
species diversity
induced mutations
genetic diversity
hybridisation
Assertion: Cattle breeds can be improved by superovulation and embryo transplantation.
Reason: Superovulation in high milk-yielding cows is induced by hormonal injection.
If both Assertion and Reason are true and Reason is the correct explanation of Assertion
If both Assertion and Reason are true but Reason is not the correct explanation of Assertion
If Assertion is true but Reason is false
If both Assertion and Reason are false.
Assertion : Agrobacterium tumefaciens is popular in genetic engineering because this bacterium is associated with the roots of all cereal and pulse crops.
Reason : A gene incorporated in the bacterial chromosomal genome gets automatically transferred to the crop with which the bacterium is associated.
If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion
If both Assertion and Reason are true but the Reason is not the correct explanation of the assertion
If Assertion is true but Reason is false.
If both Assertion and Reason are false.
Somaclonal variation is seen in
tissue culture grown plants
apomiets
polyploids
vegetatively propagated plants.
Cultivation of Bt cotton has been much in the news. The prefix Bt means
"Barium-treated" cotton seeds
"Bigger thread" variety of cotton with better tensile strength
produced by "biotechnology" using restriction enzymes and ligases
carrying an endotoxin gene from Bacillus thuringienesis.
An example of gene therapy is
production of injectable hepatitis B vaccine
production of vaccines in food crops like potatoes which can be eaten
introduction of gene for adenosine deaminase in persons suffering from Severe Combined Immuno-deficiency (SCID)
production of test tube babies by artificial insemination and implantation of fertilized eggs
Pests which only feed and oviposit on crop are called
major pests
minor pests
accidental pests
occasional pests
Hirudin is
a protein produced by Hordeum vulgare, which is rich in lysine
a toxic molecule isolated from Gossypium hirsutum, which reduces human fertility
a protein produced from transgenic Brassica napus, which prevents blood clotting
an antibiotic produced by a genetically engineered bacterium, Escherichia coli.
