From Darwin and Mendel to Gmo
From Darwin and Mendel to GMO
DNA is the blueprint for life on earth. The structure of DNA was discovered in the 1950’s, and by the 1970’s scientist were able to cut DNA from one organism and place it into the DNA of another organism. But, long before recombinant DNA, two scientists laid the basis.
Mendel was an Austrian monk who cross-bred pea plants in his monastery garden. Mendel looked at the phenotypic expression of genes like the colour of the flowers, the height of the plants and the shape of the peas. Mendel theorised that “factors” or hereditary units were being passed from parents to offspring.
At more or less the same time, Englishman Charles Darwin was gathering information that would lead to big advances in the biological sciences. The work that he did off the coast of South America on the Galapagos Islands is most famous. Darwin found evidence of extinct animals that resembled present day species. Darwin theorised that modern species had evolved from earlier species. Darwin also theorised that organisms with the more favourable characteristics were more likely to survive. This process of natural selection is linked to hybrid breeding.
Hybrid breeding is when pollination is controlled and two lines of inbred plants are crossed. The advantage of hybrid breeding is that you will get stronger plants and better crops. This is called “hybrid vigor”. This is especially easy to do with corn plants because of the way they reproduce.
The scientific process of hybrid crossing in corn can start when the female silks develop. When two pure bred varieties of corn are planted in alternating rows in a field scientists could remove or cover the tassels of one variety so that only the second variety would release pollen into the field. The ear harvested from the de-tasseled corn would have the hybrid seeds. This process produces a single crossing. For more hybrid vigor, scientists can use double-crossing. Two pure bred parents A and B are crossed at the same time as two other pure-bred parents C and D. The offspring which are now hybrids AB and CD are crossed together. The hybrid offspring of this crossing will have the characteristics of all four parents ABCD. This ABCD variety then has two generations of hybrid vigor inherited from the parents. US farmers started using hybrid seeds in the mid 1920’s and by 1930 it really started taking off. In 2003 99% of US corn was grown from hybrid seeds.
From this point of growing vigorous hybrid plants, science has advanced into a field now known as biotechnology. According to Wikipedia, “Biotechnology is the use of living systems and organisms to develop or make useful products.”
Biotechnology has actually been around for a long time, long before it had an actual name. Things that humans have done for ages like growing crops, raising animals, the making of wine and cheese and using yeast to make bread, all form part of biotechnology. Farming gave people control over their food supply. In the book Civilization, Explorations and Conquest it says the following about farming, “It was one of the most important developments in the history of mankind.”(42). Humans soon learnt how to manipulate traits in animals and plants by selective breeding. This now all falls under biotechnology.
There are many current and future uses of biotechnology. DNA finger printing helps the justice system to catch up with criminals and to identify the remains of people. This works because each person has a unique base-pair sequence in their DNA. Biotechnology can also be used in the medical field. By using recombinant DNA technology, it is possible for scientists to make insulin to treat diabetes. Human growth hormone, which is used to treat children with growth problems, can now also be made using recombinant DNA technology. Cloned skin can be grown in a laboratory and that helps burn victims.