Recently, a picture in the newspaper caught my attention. It showed two newborn marmoset twins (a species of monkey), that glowed green under ultraviolet light. My first reaction was a mixture of awe and excitement. Was this some new discovery of an animal, in some remote part of the world? It was so beautiful and unusual. But then, my eyes went towards the heading that read, ‘Glowing monkeys spark an outrage’. So definitely, these were no fairytalish creatures I had thought them to be, but something more complex. And because the word “TRANSGENIC” was attached, was exactly why the deep complexities arose and later, the controversies.
Thus, began my research. A transgenic animal is one that carries a foreign gene that has been deliberately inserted into its genome. The foreign gene is constructed using recombinant DNA methodology. This ability to genetically engineer species of animals to bring about desirable traits, is indeed a major breakthrough in the field of biotechnology.
The nucleus of all cells in every living organism contains genes made up of DNA. These genes store information that regulates how our bodies form and function. Genes can be altered artificially, so that some characteristics of an animal are changed. For example, an embryo can have an extra, functioning gene from another source artificially introduced into it, or a gene introduced which can knock out the functioning of another particular gene in the embryo.Animals that have their DNA manipulated in this way are knows as transgenic animals.
However, transgenesis would be successful, only if the inserted genes are inherited by the offspring. Also, the success rate for transgenesis is very low and the transgenic animal has to be mated or cloned for the required results.There are three basic methods of producing transgenic animals: DNA micro injection, retrovirus-mediated gene transfer and embryonic stem cell-mediated transfer.Gene transfer by microinjection is the predominant method used to produce transgenic farm animals. Since the insertion of DNA results in a random process, transgenic animals are mated to ensure that their offspring acquire the desired transgene. However, the success rate of producing transgenic animals individually by these methods is very low and it may be more efficient to use cloning techniques to increase their numbers. For example, gene transfer studies revealed that only 0.6% of transgenic pigs were born with a desired gene after 7,000 eggs were injected with a specific transgene.
There are mainly two reasons for these animals being produced. First, they are used as disease models, for researching effective treatments for diseases in humans. E.g. this cannot be done using normal mice, but genetically engineered ones, by introducing the requisite genes in them. Second, for acquiring specific economic traits. For instance, transgenic cattle were created to carry particular human proteins that can be used to treat human emphysema.
Significantly, unlike the GM crops where India was a late starter and, thus, lagged far behind other nations, in the case of GM and transgenic animals, the country has managed to make some headway.Indeed, India has already developed transgenic fish that grows several times faster than its natural counterpart. Some other Asian countries are also engaged in such endeavours, making Asia the world leader in producing transgenic fish.
Transgenic animals have a host of advantages in the fields of medicine, agriculture and industry. In medicine, it can be used for organ transplant and hence save the lives of many human beings, transgenic cows produce a particular substance that help increase red blood cells in men. In agriculture, it helps in improving the quantity and quality of livestock. In industry also, it is used for material fabrication and material safety testing. For e.g. In 2001, two scientists at Nexia Biotechnologies in Canada spliced spider genes into the cells of lactating goats. The goats began to manufacture silk along with their milk and secrete tiny silk strands from their body by the bucketful. By extracting polymer strands from the milk and weaving them into thread, the scientists can create a light, tough, flexible material that could be used in such applications as military uniforms, medical microsutures, and tennis racket strings.
However, the case of the transgenic animals have sparked off other issues as well. Ethical concerns top this list of isues. These include the idea of lab animal welfare, revolving around the notion that the health and welfare of other living creatures are being neglected in giving prominence to the health and welfare of Man. It also has other environmental concerns. Genetically engineered animals could pose a serious threat to the environment if they escape and introduce their engineered genes into wild populations. Genetically engineered insects, shellfish, fish and other animals that can easily escape, are highly mobile, and that readily adapt to life in the wild are of particular concern, particularly if they are more successful at reproduction than their natural counterparts. Nonnative insects, fish, mussels, mice and rats have all done extensive environmental damage, suggesting that engineered varieties could have similar effects if they escaped from their breeding facilities.
I started off by talking about the marmoset monkeys.The fluorescent protein introduced into their genes were responsible for the green glow. It is argued that monkeys would make better models for human diseases, as they are closer to humans than mice and could help in the search for deadly diseases such as Parkinsons. But this has raised other concerns as well. It raises the prospect of deliberately breeding monkey colonies with genetic defects that cause incurable diseases.
So the entire controversy surrounding transgenic animals ends with a question mark. On one hand, lies the attractive proposition of designing animals to suit your tastes, preferences and needs, including choosing the colour, texture, and even the temperament of the animals. And who knows, first it was plants, then animals, next it could be very well, human beings waiting next in line to be genetically modified. You never know, Spiderman may indeed become a reality tomorrow, thanks to transgenesis! On the other hand, the most essential question arises. Should Man be allowed to play God? Can so much tampering with Nature result in unforeseeable disastrous consequences in future? Only, time will tell. Till then, we can only guess and hope for the best…
[Image courtesy: http://www.labnews.co.uk/cms_images/Image/060115_glowing_pig_02a.jpg]