Back to irreducible complexity (Introduction)

by David Turell , Thursday, January 28, 2010, 17:07 (5412 days ago) @ David Turell

One more column from the theistic philosopher. In this column he describes the chicken and egg problem for Darwinists. The current studies show how a complex mechanism is present in current single-celled life, and of course multicellular life, to drive DNA to somatic variation to respond to challenges. It looks pre-planned to allow for evolution once life starts. That has been my observation all along. Evolution is planned for in genetic material and the other mechanisms that influence it. -The problem is: did original life start with these mechanisms in place, or did life 'evolve' really with no way to evolve in the first place? Darwin folks kick this back to 'origin-of-life to escape dealing with the issue. -Please look at the link provided to go to James Shapiro's review from which this philosophic comment derives. The philosopher first:-http://darwins-god.blogspot.com/2010/01/evolution-of-serendipity.html-Shapiro: The whole article is available below the abstract:-http://www.mobilednajournal.com/content/1/1/4-Shapiro's conclusions below:-Conclusion: a 21st century view of evolutionary change
Our ability to think fruitfully about the evolutionary process has greatly expanded,thanks to studies of mobile DNA. Laboratory studies of plasmids, transposons,retrotransposons, NHEJ systems, reverse transcription, antigenic variation in prokaryotic and eukaryotic pathogens, lymphocyte rearrangements and genome reorganization in ciliated protozoa have all made it possible to provide mechanisticexplanations for events documented in the historical DNA record [6]. We know thatprocesses similar to those we document in our experiments have been majorcontributors to genome change in evolution. Using our knowledge of genome restructuring mechanisms, we can generate precise models to account for many duplications, amplifications, dispersals and rearrangements observed at both the genomic and proteomic levels.
The genome DNA record also bears witness to sudden changes that affect
multiple characters at once: horizontal transfer of large DNA segments, cell fusionsand WGDs. These data are not readily compatible with earlier gradualist views on thenature of evolutionary variation. However, we are now able to apply the results offindings on the regulation of natural genetic engineering functions in the laboratoryand in the field to make sense of the DNA record. Cell fusions and WGDs are eventswe know to activate DNA restructuring functions (Tables 3 and 4). Thus, it is notsurprising that bursts of intracellular horizontal transfer, genome reduction andgenome rearrangement follow these initial abrupt changes in the cell's DNA. How anewly symbiotic cell or one with a newly doubled genome manages the transition to astable genome structure that replicates and transfers reliably at cell division is anotherimportant subject for future research. The lessons we learn about silencing mobileDNA by internal deletion [12] and RNA-directed chromatin modification [167] arelikely to prove helpful starting points.
Although there remain many gaps in our knowledge, we are now in a position
to outline a distinctively 21st century scenario for evolutionary change. The scenarioincludes the following elements:
(1) hereditary variation arises from the non-random action of built-in
biochemical systems that mobilize DNA and carry out natural genetic
engineering;
(2) major disruptions of an organism's ecology trigger cell and genome
restructuring. The ecological disruptions can act directly, through stress on
individuals, or indirectly, through changes in the biota that favour unusual
interactions between individuals (cell fusions, interspecific hybridizations).
Triggering events continue until a new ecology has emerged that is filled
with organisms capable of utilizing the available resources;
(3) ecologically-triggered cell and genome restructurings produce organisms
which, at some frequency, will possess novel adaptive features that suit the
altered environment. Novel adaptive features can be complex from the
beginning because they result from processes that operate on pre-existing
functional systems, whose components can be amplified and rearranged in
new combinations. Competition for resources (purifying selection) serves
to eliminate those novel system architectures that are not functional in the
new ecology;
(4) once ecological stability has been achieved, natural genetic engineering
functions are silenced, the tempo of innovation abates, and microevolution
can occur to fine-tune recent evolutionary inventions through successions
of minor changes.
This 21st century scenario assumes a major role for the kind of cellular
sensitivities and genomic responses emphasized by McClintock in her 1984 Nobel
Prize address [1]. Such a cognitive component is absent from conventional
evolutionary theory because 19th and 20th century evolutionists were not sufficiently knowledgeable about cellular response and control networks. This 21st century viewof evolution establishes a reasonable connection between ecological changes, cell and organism responses, widespread genome restructuring, and the rapid emergence of adaptive inventions.