Doing the impossible again. More testing ToE in the lab.

[wattsr1]

Hi All,



Below is an example of testing a hypothesis within ToE, namely the plausibility of “bet hedging” evolving by random mutation + natural selection within a population. Bet hedging is the existence of several different genotypes within a population which allow a population of organisms to quickly adapt to fluctuating environments.

There is nothing different about this, than using the lab to test a hypothesis about something that happened in the recent past. There is nothing different about this, than using the lab to test hypotheses about processes that operate now, but which cannot be observed - for example what happens inside stars or atoms, what happens inside clouds high up in the sky, or what happens between particles of light and atoms in the atmosphere.


You will never see a YEC or an IDer offer anything comparable to this.

=========================

At this link:-

http://blog.lib.umn.edu/denis036/thi...on_of_bet.html

is a good review of the article reported under this abstract:-

http://www.ncbi.nlm.nih.gov/pubmed/19890329


The conclusion of the research is interesting (references omitted, highlighting mine):-

Owing to the historical nature of the evolutionary process, the origins of most adaptive phenotypes are obscure. Here we have provided a mechanistic account of the adaptive evolution of a widespread trait. Bet hedging arose as an adaptation to fluctuating selection imposed by an exclusion rule and bottleneck, two population processes that are likely to play a key role in the evolution of stochastic phenotype switching in nature. Insight into the underlying molecular detailsreveals how evolution tinkered with central metabolism to generate a strategy that could reasonably—one might think—have taken tens of thousands of generations to evolve. The rapid and repeatable evolution of bet hedging during our experiment suggests it may have been among the earliest evolutionary solutions to life in variable environments, perhaps even preceding the evolution of environmentally responsive mechanisms of gene regulation.

Note the words “mechanistic account”, “molecular details”, “evolution tinkered with central metabolism”? They also express some amazement that this system of bet hedging could evolve quickly. Furthermore this is another example of something having its origins perhaps in deep time. It appears that many of our important genes have their origins in the time when the only life forms on earth were the billions of gadzillions of trillions of bacteria feeding, breeding and dying in a million different environments across a few billion years in time, until complex multicellular life came along.

For those who doubt the importance of mutation. They went searching for them and compared genotypes with the original ancestral genotype:-

Using whole-genome re-sequencing, the entire 6.7-megabase-pair genome of 1B4 was analysed to unravel its mutational history. Nine mutations separating 1B4 from the original ancestor were identified, confirmed by Sanger sequencing, and ordered by inspection of the affected loci in the preceding genotypes. With the exception of the final mutation, all mutations involved non-synonymous changes at loci previously demonstrated to be mutational targets in the evolution of wrinkly spreader types. The final mutation was a single non-synonymous nucleotide change in carB (Arg674Cys), which encodes the large subunit of carbamoylphosphate synthetase (CarAB, EC 6.3.5.5), a central enzyme of the pyrimidine and arginine biosynthetic pathways.

To test the fitness of their lineages, they allowed them to compete with each other and with the ancestral organism:-

Although bet hedging facilitated the long-term persistence of 1B4, the evolutionary emergence of this genotype required it to reach a detectable frequency within a selection round. To examine if 1B4 owed its emergence to a higher fitness than its immediate ancestor (1A4), we competed these two genotypes in static microcosms, the environment in which 1B4 emerged. This indicated that 1B4 was indeed more fit than 1A4 (one-sample t-test, n = 8, P = 0.0002;).

[snip]

Repeated single-cell bottlenecks can drive the fixation of random deleterious mutations, causing a decline in fitness. To test if this had occurred during our experiment, we measured the fitness of all genotypes in the 1B4 lineage relative to the original ancestor in both static and shaken microcosms. This revealed no evidence for a decrease in fitness. Interestingly, the results indicate non-transitive fitness interactions between some consecutive genotypes (for example, 1A4 is more fit than 1B4 relative to 1A0, but less fit than 1B4 during direct competition).

Anyway, just another example of experimentation in evolution, something which many insist, cannot be done.




Regards, Roland



REFERENCE

Hubertus J. E. Beaumont, Jenna Gallie, Christian Kost, Gayle C. Ferguson & Paul B. Rainey, “Experimental evolution of bet hedging”, Nature 462, 90-93 (5 November 2009) | doi:10.1038/nature08504; Received 7 July 2009; Accepted 15 September 2009

[FreezBee]

Great post, Roland

Anyway, just another example of experimentation in evolution, something which many insist, cannot be done.

Yes, there are actuslly quite a lot of experimentation in evolution, but the creationists are only looking for something spectacular such as a crocoduck -- which isn't something expected by the theory of evolution.


- FreezBee

[wattsr1]

Great post, Roland



... which isn't something expected by the theory of evolution.


- FreezBee

Ah, so ToE can't be falsified then?


Regards, Roland