Genetically Engineered Foods Essays - Biology, Genetic Engineering

Genetically Engineered Foods Essays - Biology, Genetic Engineering Genetically Engineered Foods Introduction The use of genetically engineering in agriculture and food production has an impact, not only on the environment and biodiversity, but also on human health. Therefore, thorough biosafety assessment requires, not only an evaluation of environmental impacts of genetically engineered organisms, but also an assessment of the risks that genetically engineered food pose for the health of consumers. Let us take deeper look at some of the aspects related to genetically engineered foods. What is Genetic Engineering? Genetic engineering is a laboratory technique used by scientists to change the DNA of living organisms. DNA is the blueprint for the individuality of an organism. The organism relies upon the information stored in tits DNA for the management of every biochemical process. The life, growth and unique features of the organism depend on its DNA. The segments of DNA, which have been associated with specific features or functions of an organism, are called genes. Molecular biologists have discovered many enzymes, which change the structure of DNA in living organisms. Some of these enzymes can cut and join strands of DNA. Using such enzymes, scientists learned to cut specific genes from DNA and to build customized DNA using these genes. They also learned about vectors, strands of DNA like viruses, which can infect a cell and insert themselves into its DNA. Scientists started to build vectors, which incorporated genes of their choosing and used vectors to insert these genes into the DNA of living organisms. Genetic engineers believe that they can improve the foods we eat by doing this. At first glance, this might look exciting to some people. Deeper consideration reveals some advantages and serious dangers. What are the advantages of Genetically Engineered Food? Genetic engineering gives todays researchers considerable advantages in plant breeding programs. Predictability Scientist can identify the specific gene for a given trait, make a copy of that gene for insertion into a plant, and be certain that only the new gene is added to the plant. This eliminates the backcrossing, traditional plant breeders must do to eliminate extraneous undesired genes that are frequently introduced when using cross-hybridization. Significant acceleration of the development timetable. New technique takes about 5 years to remove the undesirable traits compared to 12 years of process with the traditional techniques. Plant breeders do not use recombinant DNA techniques exclusively. Instead they use a combination of new and traditional methods to provide a plant with quality, yield, weather and pest resistance and other desirable traits. Improved quality with more choices for the customers. Genetically engineered food especially fruits and vegetables allow to have plenty of time for shipping and sale and it helps to keep the them stay ripe without getting rotten. Some of the fruits and vegetables need warm climates to grow, so most off-season store them must travel a long way after they are picked. One example is the Flavr Savr tomatoes. To survive their journey intact, tomatoes are picked while they are green, which is a food which is a good way to avoid bruising, but which results in a tomato that is often described as having the consistency and mouth-feel of a tennis ball. In the case of Flavr Savr tomatoes, the company solved the rotting problem by inserting a reversed copy- an antisense gene of the gene that encodes the enzyme that results in tomato spoilage. This suppresses the enzyme that results in rotting, allowing the tomato to stay ripe, but not rot, up to 10 daysplenty of time for shipping and sale. Refrigeration is not necessary. What are the dangers of Genetically Engineered Food? Is it safe to eat? There has been no adequate testing to ensure that extracting genes that perform an apparently useful function as part of that plant or animal is going to have the same effects if inserted into a totally unrelated species. To consumers, most genetically engineered foods are essentially foods with added substances, usually proteins. This is because genes are translated into proteins by cells. Therefore, when a genetic engineer adds, say, a bacterial gene to a tomato, he or she is essentially adding a bacterial protein to that tomato. In most cases these added proteins would likely prove safe for human consumption. Nevertheless, just as with conventional food additives,

Begash (Kazakhstan)

Begash (Kazakhstan) Begash is a Eurasian pastoralist campsite, located in Semirchye in the piedmont zone of the Dzhungar Mountains of southeastern Kazakhstan, which was occupied episodically between ~2500 BC to AD 1900. The site is located at about 950 meters (3110 feet) above sea level, in a flat ravine terrace enclosed by canyon walls and along a spring-fed stream. Archaeological evidence at the site contains information about some of the earliest pastoralist Steppe Society communities; the important archaeobotanical evidence suggests Begash may have been on the route which moved domestic plants from the point of domestication into the broader world. Timeline and Chronology Archaeological investigations have identified six major phases of occupations. Phase 6 (cal AD 1680-1900), HistoricPhase 5 (cal AD 1260-1410), MedievalPhase 4 (cal AD 70-550), Late Iron AgePhase 3 (970 cal BC-30 cal AD), Early Iron AgePhase 2 (1625-1000 cal BC), Middle-Late Bronze AgePhase 1 (2450-1700 cal BC), Early-Middle Bronze Age A stone foundation for a single house is the earliest structure, built at Begash during Phase Ia. A cist burial, characteristic of other late Bronze Age and Iron Age kurgan burials, contained a cremation: near it was a ritual fire pit. Artifacts associated with Phase 1 include pottery with textile impressions; stone tools including grinders and micro-blades. Phase 2 saw an increase in the number of houses, as well and hearths and pit features; this last was evidence of roughly 600 years of periodic occupation, rather than a permanent settlement. Phase 3 represents the early Iron Age, and contains the pit burial of a young adult woman. Beginning about 390 cal BC, the first substantial residence at the site was built, consisting of two quadrilateral houses with central stone-lined fire-pits and hard-packed floors. The houses were multi-roomed, with stone lined postholes for central roof support. Trash pits and fire-pits are found between the houses. During Phase 4, occupation at Begash is again intermittent, a number of hearths and trash pits have been identified, but not much else. The final phases of occupation, 5 and 6, have substantial large rectangular foundations and corrals still detectable on the modern surface. Plants from Begash Within soils samples taken from the Phase 1a burial cist and associated funerary fire pit were discovered seeds of domesticated wheat, broomcorn millet and barley. This evidence is interpreted by the excavators, an assertion supported by many other scholars, as indication of a distinct route of transmission of wheat and millet from the central Asian mountains and into the steppes by the late 3rd millennium BC (Frachetti et al. 2010). The wheat consisted of 13 whole seeds of domesticated compact free-threshing wheat, either Triticum aestivum or T. turgidum. Frachetti et al. report that the wheat compares favorably to that from the Indus Valley region in Mehrgarh and other Harappan sites, ca. 2500-2000 cal BC and from Sarazm in western Tajikistan, ca. 2600-2000 BC. A total of 61 carbonized broomcorn millet (Panicum miliaceum) seeds were recovered from various Phase 1a contexts, one of which was direct-dated to 2460-2190 cal BC. One barley grain and 26 cerealia (grains unidentified to species), were also recovered from the same contexts. Other seeds found within the soil samples are wild Chenopodium album, Hyoscyamus spp. (also known as nightshade), Galium spp. (bedstraw) and Stipa spp. (feathergrass or spear grass). See Frachetti et al. 2010 and Spengler et al. 2014 for additional details. Domesticated wheat, broomcorn millet and barley found in this context is surprising, given that the people who occupied Begash were clearly nomadic pastoralists, not farmers. The seeds were found in a ritual context, and Frachetti and colleagues suggest that the botanical evidence represents both a ritual exploitation of exotic foods, and an early trajectory for the diffusion of domestic crops from their points of origin into the broader world. Animal Bones The faunal evidence (nearly 22,000 bones and bone fragments) at Begash contradicts the traditional notion that the emergence of Eurasian pastoralism was sparked by horse riding. Sheep/goat are the most prevalent species within the assemblages, as much as 75% of identified minimum number of individuals (MNI) in the earliest phases to just under 50% in Phase 6. Although distinguishing sheep from goats is notoriously difficult, sheep are much more frequently identified in the Begash assemblage than goats. Cattle are the next most frequently found, making up between 18-32% of the faunal assemblages throughout the occupations; with horse remains not present at all until ca 1950 BC, and then in slowly increasing percentages to around 12% by the medieval period. Other domestic animals include dog and Bactrian camel, and wild species are dominated by red deer (Cervus elaphus) and, in the later period, goitered gazelle (Gazella subgutturosa). Key species at the earliest Middle and Bronze age levels at Begash indicates that sheep/goats and cattle were the predominant species. Unlike other steppe communities, it seems apparent that the earliest phases at Begash were not based on horse riding, but rather began with Eurasian pastoralists. See Frachetti and Benecke for details. Outram et al. (2012), however, have argued that the results from Begash should not be considered necessarily typical of all steppe societies. Their 2012 article compared proportions of cattle, sheep and horses from six other Bronze Age sites in Kazakhstan, to show that dependence on horses seems to varied widely from site to site. Textiles and Pottery Textile-impressed pottery from Begash dated to the Early/Middle and Late Bronze ages reported in 2012 (Doumani and Frachetti) provide evidence for a wide variety of woven textiles in the southeastern steppe zone, beginning in the early Bronze Age. Such a wide variety of woven patterns, including a weft-faced cloth, implies interaction between pastoral and hunter-gatherer societies from the northern steppe with pastoralists to the southeast. Such interaction is likely, say Doumani and Frachetti, to be associated with trade networks postulated to have been established no later than the 3rd millinennium BC. These trade networks are believed to have spread animal and plant domestication out of the along the Inner Asian Mountain Corridor. Archaeology Begash was excavated during the first decade of the 21st century, by the joint Kazakh-American Dzhungar Mountains Archaeology Project (DMAP) under the direction of Alexei N. Maryashev and Michael Frachetti. Sources This article is a part of the About.com guide to the Steppe Societies, and the Dictionary of Archaeology. Sources for this article are listed on page two. Sources This article is a part of the About.com guide to the Steppe Societies, and the Dictionary of Archaeology. Betts A, Jia PW, and Dodson J. 2013 The origins of wheat in China and potential pathways for its introduction: A review. Quaternary International in press. doi: 10.1016/j.quaint.2013.07.044 d’Alpoim Guedes J, Lu H, Li Y, Spengler R, Wu X, and Aldenderfer M. 2013. Moving agriculture onto the Tibetan plateau: the archaeobotanical evidence. Archaeological and Anthropological Sciences:1-15. doi: 10.1007/s12520-013-0153-4 Doumani PN, and Frachetti MD. 2012. Bronze Age textile evidence in ceramic impressions: weaving and pottery technology among mobile pastoralists of central Eurasia. Antiquity 86(332):368-382. Frachetti MD, and Benecke N. 2009. From sheep to (some) horses: 4500 years of herd structure at the pastoralist settlement of Begash (south-eastern Kazakhstan). Antiquity 83(322):1023-1027. Frachetti MD, and Maryashev AN. 2007. Long-Term Occupation and Seasonal Settlement of Eastern Eurasian Pastoralists at Begash, Kazakhstan. Journal of Field Archaeology 32(3):221-242. doi: 10.1179/009346907791071520 Frachetti MD, Spengler RN, Fritz GJ, and Maryashev AN. 2010. Earliest direct evidence for broomcorn millet and wheat in the central Eurasian steppe region. Antiquity 84(326):993–1010. Outram AK, Kasparov A, Stear NA, Varfolomeev V, Usmanova E, and Evershed RP. 2012. Patterns of pastoralism in later Bronze Age Kazakhstan: new evidence from faunal and lipid residue analyses. Journal of Archaeological Science 39(7):2424-2435. doi: 10.1016/j.jas.2012.02.009 Spengler III RN. 2013. Botanical Resource Use in the Bronze and Iron Age of the Central Eurasian Mountain/Steppe Interface: Decision Making in Multiresource Pastoral Economies. St. Louis, Missouri: Washington University in St. Louis. Spengler III RN, Cerasetti B, Tengberg M, Cattani M, and Rouse L. 2014. Agriculturalists and pastoralists: Bronze Age economy of the Murghab alluvial fan, southern Central Asia. Vegetation History and Archaeobotany in press. doi: 10.1007/s00334-014-0448-0 Spengler III RN, Frachetti M, Doumani P, Rouse L, Cerasetti B, Bullion E, and Maryashev A. 2014. Early agriculture and crop transmission among Bronze Age mobile pastoralists of Central Eurasia. Proceedings of the Royal Society B: Biological Sciences 281(1783). doi: 10.1098/rspb.2013.3382