June 1, 2007 | David F. Coppedge

Origin of Multicellularity: Back to the Drawing Board

Micro-RNAs have been found in green algae.  So?  What’s the big deal?  If you read the statements in Nature,1 it sounds like evolutionary biologists consider it a big, bad deal:

  • The discovery, made independently by two labs, dismantles the popular theory that the regulatory role of microRNAs in gene expression is tied to the evolution of multicellularity.
  • The finding is as startling as the discovery ten years ago that the nematode Caenorhabditis elegans has 19,000 genes, just 1,000 short of the human count…
  • “People were shocked that the complexity of the genomes in these simpler creatures was similar to our own,” he [Gregory Hannon, Cold Spring Harbor Laboratory] says.  Now it seems that the RNA in simple unicellular organisms could be as complex as that in higher creatures.
  • This [lack of microRNA in algae], combined with the fact that RNA sequences differ between plants and animals, helped give rise to the idea that microRNAs evolved independently in plant and animal lineages as parts of complex regulatory mechanisms associated with multicellularity.  Now it seems that these molecules may predate that evolutionary development.
  • “It shows how basing conclusions on studies of just one or two model organisms can really lead you astray in terms of how you think about evolutionary processes,” says Jim Umen from the Salk Institute in La Jolla, California.
  • Nobody knows why such a simple organism needs microRNAs, nor how or when they first appeared.

One thing was not under dispute, however: evolution.  “Whatever their role, their presence indicates that microRNAs could be much more ancient than previously thought; they might have persisted for more than a billion years.

1Lucy Odling-Smee, “Complex set of RNAs found in simple green algae: Single-celled organisms aren’t as basic as they seem,” Nature 447, 518 (31 May 2007) | doi:10.1038/447518b.

See it again?  The incorrigibility of Darwinists (e.g., 05/10/2007 commentary).  No amount of contrary evidence has the power to release the vice-like grip of evolutionary thinking on their minds.  To shield the audience from these embarrassments, they just turn up the fogma machines (05/14/2007 commentary) and the show goes on.

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Categories: Genetics

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