Is Our Food Safe They also found ways of storing food so that even in winter when fresh food was scarce there was something to eat Drying smoking salting and pickling all helped to preserve food until it was needed This photograph from 1939 shows a woman sorting peas in her storeroom with the previous year’s preserved fruits and vegetables in jars and cans on the shelves and floor around her Developing societies As societies and civilizations developed farming methods became increasingly organized and sophisticated Explorers and traders brought new foods from distant lands expanding the range of foods available The nineteenth and twentieth centuries were periods of rapid progress Electricity and machinery speeded up many processes previously done by hand while steam ships trains and airplanes reduced journey times Some scientists unraveled the secrets of genetics and inheritance while others investigated chemicals They studied microbes and developed ways of combating them New materials such as plastic were invented and household appliances such as refrigerators and freezers became commonplace Everyday life was transformed 8
FORUM People hold different views about the merits of traditional versus modern farming methods I believe there is a real and prosperous future for the traditional family farm in some cases on a more diversified basis although I know very many farmers have already taken those steps I would be astonished and dismayed if we were to see the disappearance of the traditional family farm Margaret Beckett UK environment secretary 2001 There is a need to continue to intensify farming Organic farming has a place but it will never feed the growing population of the world Bill McKelvey head of the Scottish Agricultural College 2007 Which type of farming do you think offers the best hope for the future Is our food safe to eat Modern changes All these changes have affected the food we eat Small fields have been combined to make large fields suitable for modern agricultural machinery Crop yields have been increased through the use of chemicals Animals are raised in conditions specifically calculated to allow more food to be produced more quickly and in smaller spaces Chemicals are used to improve the look or taste of food and to help it last longer Organisms can now be changed in laboratories in ways that would once have taken many years of selective breeding And global transportation means that we can have fresh food from anywhere in the world at any time of the year Modern science and agriculture together with air transport mean that a wide range of fresh fruit and vegetables from all over the world is available in our supermarkets throughout the year 9
Chapter 2 What is genetic engineering Every living thing is made up of tiny units called cells Each cell contains a set of instructions known as its genetic code or genome which controls everything that happens in the organism Genetic engineering is a technique that can be used to change the genetic code of a living organism Chromosomes and DNA The genetic information is contained in tiny double-stranded threadlike structures inside the nucleus These threads are called chromosomes and each piece of information that they carry is called a gene Geneticists often visualize the genes lined up along the Inside a cell DNA double helix Cell Chromosomes Nucleus Genes 10 chromosomes like beads on a necklace Chromosomes contain a chemical called deoxyribonucleic acid DNA which has a complicated double helix structure made up from pairs of molecules called bases There are four bases adenine A cytosine C guanine G and thymine T Each gene is made up of a specific sequence of bases This diagram shows the set of 23 chromosomes that make up the human genome Each chromosome contains many genes and each gene is made from linked base pairs of DNA 1 7 2 8 3 9 4 5 6 10 11 12 13 14 15 16 17 18 19 20 22 21 Genome X Y
Geneticists have worked out the sequence of genes and the sequence of bases that make up the genes for many organisms This means that they know which part of a chromosome carries the gene for a particular characteristic and exactly what the code is for each gene What is genetic engineering Expert View We’ll have plants that survive drought We’ll have plants that have more nutrition And we’ll have plants that have new uses and be able to benefit the farming community the economics of farming as well as the environment Roger Beachy plant pathologist talking about the benefits of genetic engineering 2007 Changing chromosomes By using enzymes to split a DNA molecule at two precise points it is possible to remove a gene from a chromosome Scientists can take a gene from the chromosome of one organism and insert it into the chromosome of another organism This means that they can transfer a characteristic of one organism into another This is the basis of genetic engineering An organism whose genetic code has been changed by genetic engineering is said to have been genetically modified often shortened to GM Swapping genes Genes can be swapped within a species to create new combinations For example a gene from a plant variety that produces a few large fruits might be transferred to the genome of a plant from the same variety that produces many small fruits giving a new variety that produces many large fruits These fruits are the result of genetic engineering between plums and apricots The fruits on the left are apriums and those on the right are pluots 11
