Question

Explain the term somaclones.

Answer 1

Hint: The term soma refers to non-germinal cells. So the names somaclone should be a giveaway to the practice of creating clones from parts other than germ cells. Thusone can relate it to tissue culture.The fragments from a plant or an animal are transferred to the artificial environment and favourable conditions for reproduction is called Tissue culture. In this method, the tissue provides such environment and favourable conditions so that it can be multiplied or grown rapidly to a full plant.

Complete answer:
Plants produced by tissue culture are called Somaclones. The name derives from the fact that the plants are genetically identical. This is possible because these clones are produced from somatic cells. Since they undergo mitosis (equational division) to give rise to new cells, they would practically contain identical genetic material.
The process of production of these clones by tissue culture is done using a technique called micropropagation. This is traditionally done in 4 steps
> Selection of mother plant
> Multiplication
> Rooting and acclimatization
> Transfer new plant to soil
Let’s have a look at the multiplication part. It is at this stage that many clones are produced. We take tissue samples produced during the first stage and increase their number. With multiple cycles, the numbers can reach from thousands to tens of thousands. Multiplication can be done using different methods and different media. One can cut the parts of a newly developed callus and multiply it in a growth medium.
The property which is exploited here is totipotency, which is the ability to regenerate a whole plant from any part. Because of this property, pieces of leaves, stems, or roots can often be used to generate a new plant given the required nutrients and plant hormones.

Note: Although Somaclones have practically identical genetic material, there are variations among the clones. These are aptly called somaclonal variants. The variations can be genotypic or phenotypic. Usually, phenotypic variations are epigenetic in origin. Genotypic variations are primarily caused by chromosome rearrangements. Changes in chromosome number (polyploidy) is another common somaclonal variation.