Tuesday, September 16, 2008

Early Life: not so simple after all

I haven't posted on evolution yet, though it is one of my main areas of interest. Quite frankly I don't know where to start. It's also so complex that I fear that I would find individual blog posts inadequate. Maybe in the future I'll change my mind. For now, I'll just post interesting tidbits.

That standard view of evolution includes the understanding that life started out simple and grew more complex as time went on. We can now understand the biology of organisms as arising from the information contained in the genes of that organism (though epigenetics is now complicating that somewhat). Evolutionary biologists then would expect simple life to have simple genes, and complex life to have more complex genes. As time went on natural selection and mutation (primarily) would add to and modify those genes, resulting in better adapted and often more complex life forms. Nevermind that even the "simplest"organism and its genes are incredibly complicated, a new study published in the journal Nature has found that the genetic code of of the Trichoplax adhaerens, thought to be one of the earliest animals, is about as complicated as the human genome. Not only is it close to being as complicated, this animal contains genes that code for organs, specialized cells, proteins, and body parts of more complex animals. In other words, this animal contains genes for body parts, organs, etc. that it doesn't have and that only animals in the future (relative to the time of this animal's origin) would have. It would seem that instead of evolution generating complexity, the complexity has preceded evolution. Likewise, in a study published this past July in the journal Science the genome of a tiny sea anemone was also found to be quite complicated, containing thousands of genes identical to those of humans.

This throws a huge monkey wrench in the standard developmental picture of life's history. The fact that there is such a huge discrepancy between the DNA of an organism and the morphology of an organism should give us pause regarding just how much we really understand about biology. As for evolution, a scientist once said (I don't remember who) that all we would need to disprove the general theory of evolution is to find a rabbit in the Cambrian period rock strata. Well, what if we've found (in a sense) a human?

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