Neutral theory

The neutral theory of molecular evolution, proposed in the 1970s by Motō Kimura, is/was a controversial theory that suggests that most mutations in an organism are, on the whole, selectively neutral, making genetic drift a more powerful mechanism of evolution than natural selection. It downplays the power of selective pressures by asserting that in general evolutionary changes are too minor to result in much actual selective advantage or disadvantage, although it acknowledges that some changes may be overwhelmingly positive or negative. Part of the implication of this is that a species can change substantially through mutation before any major change is seen; some of this holds true with current theories of pseudogenes and junk DNA mutation.[1]

This page contains too many unsourced statements and needs to be improved.

Neutral theory could use some help. Please research the article's assertions. Whatever is credible should be sourced, and what is not should be removed.

We're all Homo here
Evolution
Relevant Hominids
A Gradual Science
Plain Monkey Business
v - t - e

Neutral theory is not generally considered to represent a complete model of evolution, and does not hold strictly true in all (arguably not even in most) cases, but it adds a great deal to our understanding and ability to model evolutionary changes on a genetic level: Namely, it marked the first major drift[note 1] from purely selectionist evolutionary theory, arguing that most mutations confer a selective advantage or disadvantage. It also provides an effective null model for positive selection. It's vital to note that neutral theory is in no way "anti-selection" or "anti-Darwinian"; it simply represents another facet of understanding to the existing model of evolutionary theory.

Selectionist opposition

While neutral theory has become the consensus in population genetics, some studies have challenged it. One special example is studies of Homo sapiensgenome in comparison to Pan trogolodytes genome, in which the estimates of adaptive evolution (as the reason of genetic variation) is estimated from 0-45%. [2] One study on Capsilla grandiflora found that 40% of amino acid substitutions could be non-neutral. A study on Drosophilia melanogaster found that adaptation plays a role in evolution of small populations too. [3] Other studies found similar results by sequencing regions of the Drosophilia melanogaster genome. [4] [5]

Notes
  1. Haha, get it, because neutral theory is all about genetic drift! Haha… anyone? Tough room.
gollark: With a blockquote, thus making me inherently superior in all conceivable ways.
gollark: I posted that, bee.
gollark: Maintaining current standards of living, and also not having everyone die due to lack of food, needs roughly current technology. Maintaining current technology requires large-scale coordination. Thus, problems.
gollark: The blurb is more descriptive.
gollark: We do *need* large-scale things. I feel like that's quite important.

References
  1. On the differences between Neutral Theory and random genetic drift by Larry Moran, Sandwalk
  2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3647533/
  3. https://www.ncbi.nlm.nih.gov/pubmed/19882309
  4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1892965/
  5. https://www.ncbi.nlm.nih.gov/pubmed/11875569?dopt=Abstract
This evolution-related article is a stub.
You can help RationalWiki by expanding it.
This article is issued from Rationalwiki. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.