|The Complexity of Simplicity|
A very recent edition of Science Daily (September 8th 2008) highlights the work of biologists at Yale who have produced the full genome sequence of Trichoplax, one of nature's most primitive multi-cellular organisms. The Yale press release can be found here.
Trichoplax is a simple marine animal with a fluid-filled body cavity about 0.5mm in size. It is so unlike any other creature that it has been given its own phylum, the Placozoa. It lacks internal organs and most other tissues. It comprises a few thousand cells of four different types in three distinct layers with a single cilium which enables it to move.
Mansi Srivastava and her colleagues published the draft of the genome in the journal Nature in August 2008. They discovered that Trichoplax has one of the smallest nuclear genomes found in any multi-cellular creature with approximately 98 million base pairs and 11,500 protein-coding genes. In contrast, humans have approximately 3 billion base pairs of DNA with 20,000 protein-coding genes. Nevertheless, homologues to over 80% of Trichoplax genes are also found in the human genome.
Even the simplest forms of life are incredibly complex.
Speculations on the chemical origins of life are almost universally covered in school curricula under ‘Evolution’, despite the questionable relevance of the topic for evolution, and its rather uncertain scientific basis.
Moore, A. (2008) Nature 453:31-32