Biotechnology brings together discoveries and insights from many different kinds of science. Obviously, molecular biology, microbiology, and chemistry are important. But the scientific background of biotechnology also involves botany and zoology, mathematics and computer science, and even physics and geology. Over the last three centuries, scientists have built up the world's knowledge about the many forms of life on Earth and the basic building blocks that they all share. This body of knowledge is what makes biotech possible.

How did biotech begin?

The beginnings of biotechnology can be traced back to the beginnings of human civilization. Early peoples used cross-breeding to develop improved varieties of plants and animals; fermented foods such as bread, beer, wine, vinegar, yogurt, and cheese were made thousands of years ago.

Over the centuries, these early examples of biotechnology allowed the native civilizations ofMesoamerica, for example, to develop and grow varieties of corn that yielded five times more grain than the wild native grass. So biotechnology, as an applied science, is nothing new.

However, it was not until after the scientific revolution that we learned why these techniques work. Anton van Leeuwenhoek, the Dutch amateur who perfected the microscope and first observed microscopic life, was also the first person to see yeast, in 1680.

But it wasn't until 1866 that French biologist Louis Pasteur established that yeast and other microbes turned dough into bread, grape juice into wine, and grain mash into beer. (He also established that microbes could spoil food and developed a process -- pasteurization -- for safe keeping of food.)

At about the same time -- between 1850 and 1900 -- other European scientists made discoveries that laid the groundwork for modern biotechnology. An Austrian monk, Gregor Mendel, after experimenting with cross-breeding pea plants in his monastery garden, outlined the principles of genetic inheritance. Swiss biochemist Johann Miescher isolated a material in white blood cells that he called "nuclein" and that we now know as nucleic acid. German cytologist (a scientist who studies the structure and function of cells) Walter Flemming discovered what we now call chromosomes, and American cytologist Walter Sutton determined that these chromosomes were the carriers of the genetic traits Mendel identified. (The term "gene," to refer to the portion of a chromosome that contains a specific trait, was first coined in 1909.)

By the mid-20th century, many teams of researchers were putting together the pieces that explain how a nucleic acid, DNA (deoxyribonucleic acid), carries the genetic information of the cell, and thus of all life on Earth. In 1953 James Watson and Francis Crick developed a model of DNA -- the famous "double helix" -- and showed how the molecule could replicate itself to transmit genetic information.

These discoveries opened the floodgates to today's biotech, where researchers and technicians are manufacturing new DNA, combining DNA from different life forms, and identifying which particular sequences of DNA are responsible for genetic traits, both good ones (like pest resistance in crops) and bad ones (like cystic fibrosis in humans). By working with these DNA sequences, researchers can eliminate undesirable traits, promote desirable ones, and move the traits from one life form into another.