Synthetic Genomics is also exploring the use of algae to produce food oils and, possibly, other edible products.

Dr. Venter muses, “What if we can make algae taste like beef?”

SCIENTISTS have long been able to insert foreign genes into organisms. Human insulin is manufactured for diabetics by bacteria containing the human insulin gene. Bacterial genes are put into corn plants to give them resistance to herbicides and insects.

But until now, genetic engineering has been mainly a process of cutting and pasting a gene from one organism to another. Only one or a few genes are spliced into a cell, and considerable trial and error is required before a gene functions properly in its new host.

Synthetic biology aims to allow more extensive changes, and in a more efficient and predictable way. That would make engineering a cell more like designing a bridge or a computer chip, enabling biologists to put prefabricated components together in different combinations.

In the approach toward which Dr. Venter is driving, engineers would specify the entire genetic code of a cell  essentially the software that runs the cell  on computers, making design changes as if on a word processor. They would then press the “print” button, so to speak, and the DNA would be manufactured from its chemical components. The synthetic DNA would then be transplanted into an existing cell, where it would “boot up” and take control of the cell’s operations.

This is essentially what Dr. Venter’s team announced in May. It synthesized the million-letter genome of a simple bacterium, the longest synthetic piece of DNA produced so far, and transplanted it into a slightly different type of bacterium, which then began to replicate. A critic called the synthetic creature Synthia, a name that has started to stick.

Reaction was swift. “We heard from the pope and the president the same day,” Dr. Venter said.

President Obama immediately asked his bioethics commission to examine the potential benefits and risks of synthetic biology. The main concerns are bio-terror and bio-error  the deliberate or inadvertent creation of organisms that are toxic or ecologically harmful.