WHAT IS GENETIC ENGINEERING ?

WHAT IS GENETIC ENGINEERING ?

                      An organism’s traits are, in part determined by its DNA. which is the organism’s genetic material. DNA carries the instructions for building. maintaining, and reproducing cells. Sections of DNA called genes each control one trait by controlling how proteins are made. Proteins are important because they make up cells. Some proteins make up the cell’s structure. Other proteins are enzymes and catalysts. These proteins control chemical reactions in a cell. These reactions affect the way a cell grows and develops. Genes contribute to things such as a person’s hair color and height.They also affect whether a person will develop some diseases such as sickle-cell anemia. Genetic engineers replace genes with those of another organism or alter existing genes. By doing this, new proteins are made and an organism’s traits can be changed. Moving genes from one organism to another is not a new idea. It has been done for thousands of years. When farmers selected animals that were larger and healthier to breed 10.000 years ago. they were hoping that the offspring of those animals would inherit the beneficial traits of the animals parents. Farmers have selectively paired crops for thousands of year as well. When a farmer pollinates one plant with another, he or she is manipulating the genes of the offspring.One scientist who made great progress in discovering how traits are passed on was Gregor Mendel. Mendel is often called “the father of genetics.” He experimented on pea plants from 1856 to 1863. Through his experiments. Mendel was able to purify a desired trait in a pea plant through self-pollination. He then bred the offspring that contained the desired trait with a plant that had a different trait. By studying the results of his experiments. he formulated a theory about recessive and dominant traits. Dominant traits overshadow recessive traits. Recessive traits are-evident in offspring Recessive traits are evident in offspring only if each parent has passed down the recessive gene.

SELECTIVE BREEDING
                        Early experiments with genetics. however, are not usually thought of as genetic engineering. Instead. this is called selective breeding.which describes a transfer of genes that would not occur in nature. One of the main differences between selective breeding and genetic engineering is that selective breeding usually involves two species that are closely related.Genetic engineering, on the other hand, may involve combining the genes of two very different species. In addition, selective breeding uses natural biological processes to help create new types of crops and  live stock.When people began farming land approximately 10,000 years ago. they selected wild grasses for selective breeding. These wild grasses led to the  cultivation of crops such as wheat, rice, and maize (corn). Farmers proceeded to replant only seeds that came from particular plants because those plants produced the best product during harvest. By doing this, farmers were engaging in a practice that changed the environment to suit their purposes. Farmers also manipulated food by using microorganisms such as bacteria and yeast in the fermentation of beer and in the production of yogurt. Early on, farmers were familiar with hybrids, which were new types of plants produced by crossbreeding related varieties of plants. Selective breeding had an effect on animals as well. A male donkey was first bred with a female horse to create a mule more than 3,000 years ago. Mules were first used to transport items, and are still used today to carry goods.

 DIFFERENCES  in  SELECTIVE BREEDING
AND GENETIC ENGINEERING
                      There are three main differences between selective breeding and genetic engineering. First, selective breeding involves breeding within a species or the crossing of species that are closely related. Second. the pace of change in selective breeding isslower compared to genetic engineering. Selective breeding requires traits to be developed over several generations. whereas a genetic engineer can insert a gene from one organism Into anoher organism in a matter of days. Third. selective breeding only modifies a small number of species. Genetic engineering. however can change a whole variety of organisms for avariety of purposes. Some of the areas in which genetic engineering seeks to produce change are sewage disposal, pollution control, and drug production. The difference between genetic engineering and selective breeding can be confusing because the two fields are closely related. However, genetic engineering involves advanced scientific processes. The science behind genetic engineering is highly sophisticated and advances in the technology are being made every day.