Monsterboy said:
http://discovermagazine.com/2014/march/12-mutation-not-natural-selection-drives-evolution
how well accepted is the above theory ,is it well known ?
It is well known to those who study evolution, and often referred to as neutral drift: http://www.evolution.berkeley.edu/evosite/evo101/IIIE5bNeutraltheory.shtml[/URL]
It is definitely accepted that both selection and drift play important roles in evolution. Quantifying exactly how much of a role each plays is a more difficult question that probably has different answers depending on the system you study. There can often be important interplay between drift and selection in determining which evolutionary paths are available to an organism. Here's something I've previously written on the topic copy-pasted from a previous PF discussion [URL]https://www.physicsforums.com/threads/human-evolution-bacteria-conjugation.841969/#post-5284454[/URL]:
[quote]A few notes on long term evolution experiments (LTEE):
1. Subsequent to the 2008 PNAS paper describing the Cit+ strain, the Lenski lab published a follow up paper identifying some of the actualizing mutations behind the Cit+ phenotype: [URL]http://www.nature.com/nature/journal/v489/n7417/full/nature11514.html[/URL]. We discussed the paper in the following PF thread: [URL]https://www.physicsforums.com/threads/long-term-evolution-experiment.638509/[/URL]
2. In the 2008 PNAS paper, the authors note that all each of the 12 cultures in the LTEE had grown for long enough times such that each culture would sample all single point mutations possible in the genome. However, many evolutionary studies showed that [URL='https://en.wikipedia.org/wiki/Epistasis']epistasis[/URL] plays very important roles in evolution. The same point mutation can have different effects on an organism's phenotype depending on what other mutations are present. Thus, sampling every single point mutation cannot tell you the effect of every possible pair of single point mutations. Even though the experiment sampled all single point mutations, it has not sampled all combinations of mutations, so much of the evolutionary landscape still remains unexplored.
3. In many cases, the evolution of beneficial traits require certain permissive mutations to precede acquisition of the actualizing mutations that confer the beneficial phenotype. In the absence of the permissive mutations, the actualizing mutations can be deleterious instead. This situation appears to be the case for the evolution of the Cit+ phenotype in the Lenski experiment, and this phenomenon has also been observed in the evolution of steroid receptors: [URL]http://www.ncbi.nlm.nih.gov/pubmed/17702911[/URL]
4. In some cases, the permissive mutations confer an evolutionary benefit to the organism, so there exists an adaptive path toward the evolution of the beneficial trait (i.e. the fitness of the organism increases at all steps along the way). For example, this has been seen in the evolution of antibiotic resistance: [URL]http://www.sciencemag.org/content/312/5770/111.long[/URL] However, in the cases of the Cit+ and steroid receptor evolution, the permissive mutations seem to be neutral. Thus, evolution of these new phenotypes depended not only on natural selection, but also neutral drift. More broadly, given the pervasive roles of epistasis in evolution, neutral drift is likely continually opening and closing various potential adaptive paths towards new phenotypes, consistent with previous thoughts about the role of historical contingency on evolution. If true, this would suggest that evolution, to some extent, is fundamentally unpredictable.[/quote]
At some point, I should probably write up an Insight article on this topic.
