If the quote said the opposite, it would be in support of UCA, which it doesn't. Networks cloud the issue, which is exactly what I'm pointing out.
The problem for that outlook, which Bapteste does
not support, is that lateral gene transfer (necessary for networks) is quite rare in eukaryotes, which means a phylogenetic tree within the prokaryotes is more of a network, but it is not like that in eukaryotes, as Bapteste points out.
Also, where this is headed does effect plants and animals since it re-evaluates the concept of species and trees.
Nope. In fact, it pretty much solidifies the current understanding, particularly when one of the people most strongly pushing the network idea agrees that it isn't applicable to eukaryotes.
Bapteste, E., Brinkmann, H., Lee, J., Moore, D., Sensen, C., Gordon, P., Durufle, L., Gaasterland, T., Lopez, P., Muller, M. and Philippe, H. (2002) The analysis of 100 genes supports the grouping of three highly divergent amoebae: Dictyostellium, Entamoeba, and Mastigamoeba. Proc. Natl. Acad. Sci. U S A, 99, 1414-1419.
and...
Much of the initial concern over TOL was provoked by biologists studying the complex relationships among prokaryotes, the most primitive life forms that include bacteria and archaea. Prokaryotes have a much simpler DNA structure than eukaryotes (all other life forms). Because of this, prokaryotes often transfer their DNA via processes such as lateral gene transfer as opposed to vertical gene transfer (direct transmission form parent to progeny) which is the basis for the “phylogenetic” (evolutionary relatedness) TOL scheme.
“Surely a tree is the right model for most multi-cellular animals and plants,” Doolittle explained to PhysOrg.com. “Thus the TOL is great for fossils and museums and dinosaurs and most of visible life, over the last billion years. But unicellular eukaryotes and prokaryotes represent the bulk of the biomass and diversity of life on earth, as well as the first two-thirds of its history.”
In their paper, Doolittle and Bapteste highlight research that shows other causes of genetic modification, suggesting that evolutionary history is more complex than described by the TOL. For example, recombination, gene loss, duplication, and gene creation are a few of the processes whereby genes can be transferred within and between species, causing variation that’s not due to vertical transfer. These transfer methods give results that don’t fit on the TOL, including species that cannot be traced to a common ancestor.
http://phys.org/news92912140.html#jCp
It should be noted that Stephen Gould, in
Wonderful Life, suggested that perhaps the wide diversity of arthropods in the Cambrian was the result of variations in the genetic toolbox of a primitive arthropod-like ancestor, while there was still a great deal of interchangeability in their genomes. The thought is that later arthropods could share much less, for the same reason that versions of the same bank accounting program in COBOL become increasingly incompatible as people continue to make ad-hoc changes in the code.
Maybe so. But the evidence is incontrovertible . Oh, and my copy of Bergey's Manual of Determinative Bacteriology, seventh edition, 1969, is of mostly historical interest; the classification of bacteria has changed greatly. I have a degree in bacteriology, and I never saw a "tree" of common descent for them. Even then, it was clear that a great deal of gene-sharing had gone on. So nearly a half-century later, the breathless announcement by the popular press about prokaryotic networking, really doesn't impress anyone familiar with the literature.
Which is why those DNA analyses so precisely confirm the tree of life proposed by Linnaeus, the anatomical data, and the evidence from paleontology; they really are indicators of common descent. The fact that prokaryotes pass genes around laterally, doesn't affect eukaryotes.
Just saying...
