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Eugene Koonin steps out on Darwin Day: LUCAS, not LUCA


Eugene V. Koonin, “Darwinian evolution in the light of genomics,” Nucleic Acids Research 2009, 1-24.

The overall pattern of life’s history, he argues, may be a Forest, not a single Tree of Life [TOL]:

Evolutionary genomics effectively demolished the straightforward concept of the TOL by revealing the dynamic, reticulated character of evolution where HGT, genome fusion, and interaction between genomes of cellular life forms and diverse selfish genetic elements take the central stage. In this dynamic worldview, each genome is a palimpsest, a diverse collection of genes with different evolutionary fates and widely varying likelihoods of being lost, transferred, or duplicated. So the TOL becomes a network, or perhaps, most appropriately, the Forest of Life that consists of trees, bushes, thickets of lianas, and of course, numerous dead trunks and branches. Whether the TOL can be salvaged as central trend in the evolution of multiple conserved genes or this concept should be squarely abandoned for the Forest of Life image remains an open question. (p. 17)

Nonetheless, Koonin stands by “common ancestry,” but attenuates its meaning: “the very concept of a distinct LUCA [Last Universal Common Ancestor] becomes ambiguous, and it might be more appropriate to speak of LUCAS, the Last Universal Common Ancestral State” (p. 9). Molecular discontinuities among major groups probably indicate multiple independent originations of key systems:

Regardless of which scenario is preferred, the lack of conservation of central cellular systems among the domains of life indicates that the early stages of cell evolution involved radical changes which are hardly compatible with uniformitarianism. (p. 9)

Nucleic Acids Research has made this paper open access, so go check it out.

"The irreducible complexity characterisitc predicted by Intelligent Design implies that the fossil record will exibit a pattern of abrubt appearance of novel, fully functional, complex body plans, followed by stasis. This is precisely what we find in the fossil record. The rapid appearance, without precursors, of large amounts of biological information in the history of life, as witnessed in the numerous "explosions" of life detailed in the fossil record, provide powerful evidence for Intelligent Design." INTELLIGENT DESIGN 101 God bless you guys, may the Lord keep you and sustain you. Platonist
To me, it is articles like this that keep articles interesting. Imagine numerous trees of life, unconnected to one another. There would have to be an intelligent designer in that case!! Platonist
From what little I knew about Koonin, he seems to be interested in single celled organisms and the changes he speculates, took place prior to the Cambrian Explosion. Though he discusses multi-celled organism in places. I have not read all of this but it seems to confirm this observation. What I did read was the first six pages and then the conclusion. This seems to be a good summary of some of the more esoteric areas of evolutionary biology. Some of it is hard to digest but it represents what many of them seem to be saying. There does not seem to be any hard evidence for their speculations but the speculations are caused by the inadequacy of the traditional paradigms. This does not mean the traditional paradigm is being abandoned. A much more complex set of layers is being added to it. Again this is all speculation especially the idea that gene duplication can allow one of the genes to remain fallow and mutate till it blossoms into a new functional system for an organism. This would fit into the gene search discussed in a couple of threads a few weeks ago. What are the odds that random events would turn one gene into another gene whose protein is completely different. The Darwinian imagination is not dead, just off in a different direction. I recommend all read the background section and the conclusions section to understand the history of the evolutionary synthesis and what they are up to today. jerry
So, what he's saying is that diverse simple lifeforms converged into more complex lifeforms ... Kind of like Transformer toys that stick together to become one giant Transformer. One organism that has inherited traits from many simpler organisms. And many organisms that have inherited very different sets of traits from many simpler organisms. And here, I thought the tree of life was all but proven. QuadFather
Great, I bet Barbara Forrest thinks this new scheme is named after her... :) Joseph

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