"That's it. That's biology," he says. "That's why genomics is such a big, blossoming field. Now we can understand an organism comprehensively.
"Of course there are a lot of organisms out there. In the end, what genomics has as its goal is to understand all of the genes in all of the organisms on the entire planet."
The idea we may know all of the genes of all of the organisms on the planet may seem absurd. But to a 15th century mapmaker, the idea that someday there would be topographical maps for every continent, island and speck of land seemed equally absurd.
Biologists have an easier task before them in making maps of all living organisms than faced those early cartographers, because, as surprising as it sounds to a non-scientist, the genes of nearly all living organisms are almost identical.
Viva La Difference
Although the external differences are not subtle, most creatures are very much alike in their genetic codes. Humans and chimpanzees differ by less than 1 percent in their genes.
"For example, on the surface it would appear that cows and humans are very different," Woodson says. "Yet, when one examines the genes that make up a cow, generally the same gene or a version of the same gene is present in humans. The differences are very slight.
"Take corn and a tomato as another example. They're very different plants, but they have a lot in common genetically."
The reason for this similarity, Bennetzen says, is that nature doesnt like reinventing the wheel. "Creation of new genes is very rare, maybe happening only a few times in tens of millions of years," he says.
Scientists call this similarity "genetic conservation." Once nature finds something that works, it sticks with it, even if the organisms are strikingly different. Twenty or 30 percent of the genes in a human may be the sam
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Contact: Steve Tally
tally@aes.purdue.edu
765-494-9809
Purdue University
11-Feb-2001