Somatic hybridization is A. Mixing of two types of nuclei of somatic cells of the same species and same variety. B. Fusion of plant cell nucleus with that of animal cell. C. Fusion of the gamete nucleus with the nucleus of somatic cells. D. Fusion of cells of different species.
Hint: Somatic cells refer to the body cells. These are the cells other than reproductive cells. In this method, the protoplasm of two cells are fused to obtain the desired hybrid cells. The plant cells which do not contain cell walls are called protoplast.
Complete Answer: Somatic hybridization is the process of fusion of somatic protoplasts of two different plant species or two different plants. It leads to the formation of hybrid plants.
The process of somatic hybridization involves following steps: - Isolation of protoplast - Fusion - Identification and selection of desired cells - Culture of desired hybrid cells - Regeneration of desired cells
- The isolation of protoplast can be done using mechanical or enzymatic methods. Mechanical method involves the usage of a knife to cut the cell wall. - In enzymatic methods, Fusion of protoplast can be done using spontaneous methods or by induced fusions. The nucleus and the cytoplasm of the two cells are fused to obtain the desired hybrid products. - Selection of hybrid cells is done as the resultant mixture will contain other components as well. So, this step ensures obtaining the right cells. After this, the copies of resultant cells are made using various techniques. - Somatic hybridization does not involve a plant and animal species fusion. It is done between somatic cells of different plant species. It does not involve the fusion of gametic cells or sex cells.
So, the correct answer is option (D) which states that the somatic hybridisation involves fusion of cells of two different species.
Advantages of somatic hybridization: - Species which do not reproduce sexually, can be fused with the help of somatic hybridization. - Can also be done in sterile strains. - Cytoplasmic transfer can replace the back-cross. - Mitochondrial genomes are also generated in somatic hybrids.
Note: Hybridization is a method of fusion of two desired entities. Here, the somatic hybridization refers to the fusion of protoplasm of somatic cells. This method is highly useful but also has some limitations such as the production of viable and fertile seeds is not guaranteed always.