How does genetic engineering work?

What is a gene?

Every plant and animal is made of cells. Every cell contains a nucleus. Inside each nucleus are chromosomes, which act as containers for strands of DNA (deoxyribonucleic acid). DNA is often described as a blueprint containing all the necessary information for the structure and functioning of an organism. Genes, which are contained within strands of DNA, are the individual messages that make up the blueprint - the basic instructions for life - and each gene codes for a particular trait. Sounds simple, right? But organisms aren't machines. And no gene functions in isolation. Life is a delicate tangle of genes and organisms and environment. While advances in genetics hold incredible potential in the medical field, the genetic manipulation of food is still highly experimental, and fails to take into account the incredibly complex relationship of genes to organisms and organisms to the environment.

What is the difference between genetic engineering and traditional plant breeding?

Natural breeding techniques create new varieties by selecting traits from the multitude that already exist within an existing species. In nature, genetic diversity contains certain limits. A rose can be crossed with another variety of rose, but it can never be crossed with a mouse. Unlike natural breeding, genetic engineering consists of taking genes from one species and inserting them into another in the hopes of transferring a particular trait. For example, scientists have attempted introduce a gene for resisting the cold from an Arctic fish into tomatoes to prevent freezing. It is impossible to predict, in the long term, how transplanted genes will react within generations of organisms and in the environment.

Want to know more?

Explore an illustrated guide to the problems of genetic engineering, the complexity of gene expression and the unexpected effects so far.