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Archive for Sunday, July 16, 2000

Alphabet of creation gives writer new insight

On the Hill

July 16, 2000

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When the scientist from Northwestern University said that our week in the laboratory might lead us to a religious experience, I snapped to attention.

In a question session that followed, I asked the scientist, Rex Chisholm, for details.

He smiled and said, "Over a beer, maybe."

The setting was the Marine Biological Laboratory in Woods Hole, Mass. The laboratory was designed for a group of journalists taking part in an annual Science Writing Fellowships Program.

The first thing we did that week was watch the cells of clam eggs begin to divide. As part of the action, some spidery-looking filaments seemed to align the cell's chromosomes.

As the days passed, we figured out one of the filament's key proteins. Then we found the gene that helps create the protein.

Finally, we scratched around in search of the chemical building blocks of that gene. Those building blocks are called nucleotides. They come in four varieties. They are known by the first letters of the chemicals' names: A, C, G and T.

A spiraling strand of DNA comprises about 3 billion of these building blocks in monotonously repetitive combinations. Just last month, scientists announced they had a rough draft of their order.

By week's end, my lab partner and I had figured out a run of 187 letters within the gene we were studying. At the National Center for Biotechnology Information Web site, we typed in our 187 A's, C's, G's and T's and used a search engine to learn more about our gene.

And then I had an epiphany about life's unity.

I'd known for some time about the likenesses among cells. As science writer Boyce Rensberger says in his book "Life Itself," "A human brain cell " is not more complicated than a one-celled creature inhabiting pond scum."

That is, with some notable exceptions, cells all over creation are much alike.

But during my computer search, working now at the level of the four-letter alphabet of life, I found another level of unity among living things.

Substantial chunks of the 187-letter string of chemical building blocks showed up in a variety of creatures -- clams, fruit flies, yeasts, slime molds, octopuses and us, to name a few.

Biologists describe this by saying that some genes are highly "conserved" from species to species. But that doesn't capture the magic I felt concerning my alphabetic kinship with slime molds and yeasts.

Gazing at the computer, I felt more linked to my fellow Earthlings -- all of them.

Later that afternoon, our class cruised around some coves on a collecting vessel. Crew members dredged the waters to show us some of the squirmy things that lived below.

At one point, I lifted a jar of captured life to the sky. Larval crabs darted through the brine, and jellyfish smaller than thimbles heaved in slow pulses.

The fact that all of this life -- and mine, and yours -- rests on the pillars of four chemicals and on the toil of lowly cells trapped in monotonous self-replication does not, it seems to me, trivialize our existence. It makes it more awesome.

I didn't even need a beer to see that.

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