Introduction to Genetic Modification

Genetic modification of plants and animals by sexual crossing has been taking place for thousands of years. It began when humans decided to stay in one place rather than move from place to place in search of food. To increase the amount of food available they chose plants or animals with improved characteristics to breed, or “cross,” for the next generation. For example, they might have crossed one plant with higher yields to another plant that had increased pest resistance and then screened the plants resulting from the cross to find ones with both higher yield and better pest tolerance. Virtually every food in today’s market has been modified in this way and, as a result, most foods we eat today look little like their ancient relatives.