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Decoding the Human Body

Have you ever wondered how a chicken egg manages to grow into a chicken and not a frog? Or how a frog egg produces a frog and not a python? The answers lie in their genes, tiny sets of chemical instructions in every cell of every creature that contain its recipe. The recipe for a human being is contained in the 80,000 genes we inherit from our parents. These genes have the instructions that not only make us human but also determine things like skin color and the shape of our nose.

Last week Craig Venter, the lead scientist at Celera Corporation in Maryland, announced that his team had cracked the chemical code for every human gene.

This breakthrough is likely to lead to great medical advances. Knowing detailed information about human genes could help millions of people who suffer from illnesses caused by mistakes in their gene code. They could someday undergo genetic treatments to correct the problems. Doctors may also be able to detect and prevent illnesses like cancer and heart disease, which are linked to certain genes.

Scientists have years to go before they can pinpoint the function of every gene. "We're assembling one of the biggest jigsaw puzzles ever imaginable," said Venter.

The Code of Life
Genes are made of a special chemical called DNA. It is shaped like a very tiny, twisted ladder. The rungs of the ladder are made of four chemicals. These chemicals can appear in an almost endless variety of patterns. Each pattern forms the instruction, or code, for a specific component of the human body.

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