|
Author
|
Topic: Evolution caught in the act?
|
Kevin C. Easterday
Member
Member # 1921
|
posted 22. March 2006 13:59
Forgive my ignorance, but if this experiment was to give evidence for evolution, why didn't it seek to introduce something new? If all they did was introduce a different protein by which the bacteria could repair itself, wasn't the result just a proof of mutation, not of evolution? And wouldn't they want to show that the change was towards more efficiency and benefit to the organism?
If they had introduced a protein or proteins that made the bacterium have three flagella working in tandem, that might mean something. Am I wrong in my assumption?
Regards,
KC
IP: Logged
|
|
David L. Hagen
Member
Member # 323
|
posted 05. June 2006 13:05
Recommend reviewing this experiment in light of [http://www. John C. Sanford's work "Genetic Entropy and the Mystery of the Genome".
See: [url]http://en.wikipedia.org/wiki/John_C._Sanford John C. Sanford[/url]
See discussion at UncommonDescent.com June 1st, 2006:
[URL=http://www.uncommondescent.com/index.php/archives/1173 ]Respected Cornell geneticist rejects Darwinism in his recent book[/URL]
(From my preliminary understanding from reading the discussion)
Compare the results relative to the average distribution of functionality due to mutations.
Highly skewed mutation distribution
Sanford shows that almost all mutations are deliterous.
Selective Selection
Further, only strongly deliterous mutations are selected out. Near neutral mutations are not selected out within a band based on the Signal/Noise ratio.
Correspondingly, most favorable mutations are not positively selected for in the genome because of this Signal/Noise ratio. Consequently, Random Mutation & Natural Selection cannot secure small incremental mutations as beneficial changes (information).
Degrading Functionality
Rather the funcationality of the organism gradually degrades with accumulation of predominantly deliterous mutations.
Thus, in natural or "wild" systems, Genetic Entropy of accumulation of negative mutations from random mutations would probably overwhelm the probability of beneficial mutations such as identified in this carefully engineered experiment.
Look forward to feedback from puplation geneticists on this.
IP: Logged
|
|
David L. Hagen
Member
Member # 323
|
posted 05. June 2006 14:00
Cumulative degradation of Genome
Two related articles from the discussion at UncommonDescent June 1.
Kondrashov “Contamination of the genome by very slightly deleterious mutations: why have we not died 100 times over?” (1995, Journal of Theoretical Biology 175, 583-594).
Suzanne Estes & Michael Lynch (2003), Evolution 57, 1022-1030.
Abstract. Deleterious mutation accumulation has been implicated in many biological phenomena and as a potentially significant threat to human health and the persistence of small populations. The vast majority of mutations with effects
on fitness are known to be deleterious in a given environment, and their accumulation results in mean population fitness decline. However, whether populations are capable of recovering from negative effects of prolonged genetic bottlenecks via beneficial or compensatory mutation accumulation has not previously been tested. To address this question, long-term mutation-accumulation lines of the nematode Caenorhabditis elegans, previously propagated as
single individuals each generation, were maintained in large population sizes under competitive conditions. Fitness assays of these lines and comparison to parallel mutation-accumulation lines and the ancestral control show that, while the process of fitness restoration was incomplete for some lines, full recovery of mean fitness was achieved in fewer than 80 generations. Several lines of evidence indicate that this fitness restoration was at least partially driven by compensatory mutation accumulation rather than a result of a generic form of laboratory adaptation. This surprising result has broad implications for the influence of the mutational process on many issues in evolutionary and conservation biology.
--------------------
Compare Peter Borger's comments on robustness in biotic systems in Brainstorms - "Can some aspect of Darwinism be falsified?"
e.g., See: [url] http://www.iscid.org/boards/ubb-get_topic-f-6-t-000621-p-6 peter borger[/url]
Were these .html"compensatory mutations" or evidence of robustness in the system, or both? If both, was the recovery due to robustness in spite of the other mutations? OR due to the compensatory mutations?
IP: Logged
|
|
|
Printer-friendly view of this topic