高考英语《流行话题 语境识词4500》Unit 75　The Concerns about Genetically Modified Food素材.docVIP

高考英语《流行话题 语境识词4500》Unit 75　The Concerns about Genetically Modified Food素材 Unit 75　　The Concerns about Genetically Modified Food　　Genetic Modification (GM) has the power to save lives through its use in medicine, such as the production of insulin for diabetics or the treatment of genetic disorders. The current outcry comes when it is used to produce food. Some of these public concerns reflect real problems, but others are fuelled by misinformation and over-dramatization.　　There is nothing new about crop modification; plant breeders have been doing this since agriculture began. The wonderful range of apples or potatoes we now enjoy is the result of crossing different varieties. Cabbages, Brussels sprouts, cauliflower, kohlrabi and broccoli all originated from one botanical species.　　Modern molecule biology has enabled us to go much further. We can now isolate the gene from a particular characteristic of an organism and transfer it to another species. It is this practice of transforming a plant with alien genes -- perhaps from an animal or bacterium --that is causing all the controversy.　　There are four main concerns.　　Scientists can now take a gene for resistance to particular herbicide and transplant it to a crop: when these plants are sprayed with weedkiller, the weeds were destroyed while the crop is unharmed. A prime concern is the harmful effect this could have on the biodiversity of farmland, where so many insects, birds and other animals depend on weed species.　　Another fear is that alien genes from a GM plant could escape into a wild population of a related species. Since plants are fertilized by pollen carried through air, often for long distances, this is entirely possible. A wild species modified in this way with pesticide resistance could become a superweed, while a species that became unnaturally resistant to animals could disrupt the food chain.　　The third worry concerns a proposal to produce seeds for cereals that cannot produce next years seed