Since the times mankind took to agriculture, we have been improving our crops in order to get more yield. The tools of crop improvement are selective breeding of crops with desired characters, cross pollinating two related plants for desired characters followed by controlled self breeding. But this method of breeding has one major drawback. Nature has provided all organisms with genetic inability to breed freely with other species. An organism can breed only among those of same type. Due to this genetic blockage one species is unable to cross breed with another species. A species can breed among relatives of the same species only thus limiting the scope of improvement. There are some exceptions in nature to this like a cross between a donkey and mare is possible and results in a hinny, similarly across between a horse and jackass results in a mule but both hinny and mule are sterile.
Advances in Molecular Biology and Biotechnology have provided us with tools to do away with this genetic blockage. Biotechnology has enabled us to produce organisms with desired characters crossing all limits of species except for religious, moral and ethical issues.
The result of advances in Biotechnology and Molecular biology is Genetically Modified crops or animals popularly called GM Crops or GM Animals. Various steps in producing GM Crops /Animals can be summarized as
- Organism with desired character is identified.
- The gene( a specific sequence of DNA nucleotides that code for a specific character) is identified and cut off from the main sequence.
- This gene is attached to a carrier or vehicle called vector. Vector is either a virus or bacterium. The bacterial cells have an extra piece of DNA called plasmid. The gene is attached to plasmid and transferred back to the bacterium.
- The bacterium multiplies and produces a large no. of copies of the desire gene.
- These gene copies are then transferred to the target cells either by firing them at high velocity into the cell or through a soil bacterium Agrobacterium tumifaciens.
- The cells are then cultured using tissue culture techniques to produce GM plants.GM plants are extensively tested to find the proper working of the gene. This is done with the help of certain marker.
Genes express themselves through proteins. This hypothesis is called central dogma
DNA(Gene) ------> mRNA ------> Protein
We may not inadvertently create a similar monster world full of interspecific plants and animals, lest the God once again has to wipe the slate clean to start all over again.
The expression of gene is a complicated and controlled process through promoter and suppressor genes. These gene switch on or switch off a specific gene thus regulating its expression.
Using biotechnology it is possible to transfer non plant genes into plants.The best example of this is B.t or Bacillus thuringonsis, a naturally occurring bacterium that produces a crystalline protein lethal to insect larvae. This B.t gene has been transferred to many crops like Maize(Corn),Cotton, Brinjal etc. These are commonly called B.t Corn, B.t Cotton and B.t Brinjal respectively.
GM foods may be able to alleviate food supply to millions of the hungry people around the world. GM foods may also reduce dependence on pesticides and herbicides thus addressing the environmental issues. The GM crops will be disease resistant and will be able to tolerate increasing cold or drought or salinity. GM foods may provide us with cheap edible vaccines or specific medicines. They may also help us to clean up heavy metal contamination of the soil.
However, concerns have been raised by religious groups, environmentalists, Public interest groups, Scientists and others regarding the potential impact of GM crops on environment and health.
In the Bible there is a reference to times when mankind was able to interbreed with other organisms(Genetic isolation was absent), resulting in a world full of half human and half animals. God became angry and wiped the slate clean to start all over again.
Though GM foods have a great potential, we must proceed with utmost care to avoid unforetold damage to environment and health.
I belong to the community of teachers and I teach Life Sciences. Life Science is something what I consider 'Mother of all Sciences'. It is the way of human life. Life science encompasses practically all branches of knowledge,as life itself is dependent on all the physical and chemical parameters with in our knowledge. I write regularly write at http://myinferencesonlife.blogspot.com.