digging through my hsc stuff...
Current reproductive technologies used by humans aims to alter the gene pool of differnet organisms to improve their characteristics for human uses and purposes. These technologies include:
Artificial insemination - Sperm from males with desirable traits are collected and placed inside females' uterus to united with females' eggs to cause fertillisation. The growth of the offspring then occurs as normal inside the female. The offspring is likely to display the desired traits.
Artificial pollination - Pollen from plants with desirable traits are collected and are dusted over female stigmas by hand to cause fertillisation. Plastic bags are then used to control the process. The offspring is likely to display the desired traits.
Cloning - this involves cutting and grafting in plants. In animalsthe nucleus of a somatic cell from a choosen individual is isolated and inserted into an ennucleated egg cell. This is then implanted into a surrogate where normal growth occurs. As a result the offspring will be genetically identicle to the choosen individual.
Production of transgenic organisms - this involves transport of desired genes from one organism to another totally different organism. When a desired gene is identified and located, the same resistriction enzyme is used to cut the 2 DNA strands of the 2 different organisms. Then the enzyme ligase is used to repair and recombine the sticky ends of the cut DNA. This new modified gene is then inserted into a cell of the organism by instruments such as a gene gun. the organism will display the desired gene as a result. Transgenic species can be similarly produced by using bacteria that can infect plants with its DNA. The DNA is modified to include desired genes.
By genetically modifying plants, we can grow plants such as BT cotton which can produce its own natural pesticide and therefore are pest resistant without the use of human made pesticide. BT cotton therefore produce higher yield at lower cost, however resistance to BT may soon occur. Salmons can be modified to include the bGH gene which allows salmons to grow larger, faster. These results improve econoimical values, increase food production for humans and reduces pollution.
The genetic information in these reproductive technologies are often used repeatly on large number of specimens, to introduce predetermined characteristics that greatly increase chances of survival. This results in uniform offsprings dominanting the population over non-modified individuals and the lost of genetic variability over time.
The lost of genetic variations renders entire populations susceptible to the same disease, predator or natural changes in the environment. this drastically increases the risk of reduced population and lost of biodiversity. The effects of these organisms as food for humans are also unknown. There is also risk of contamination between genetically modified and unmodified species which may further accelerate the lost of biodiversity.
The production of transgenic organisms may initially increase the biodiversity as it introduces new characteristics into organisms. However if only one particular transgenic variety is used, over time it will most likely dominant the population with the advantages it has with their transgenic characteristics and again lost of genetic variability will result. Cloning has the potenial to increase the gene pool by reviving extinct organisms such as the Tasmanian tiger.
These reproductive technologies should be limited in both number and location to reduce risks, and its progress should be monitored at all times to prevent negative effects.
