Editing Irreducible complexity (section)

=== Methods by which irreducible complexity may evolve ===
{{further|Evolvability}}

Irreducible complexity can be seen as equivalent to an "uncrossable valley" in a [[fitness landscape]].<ref name="trotter2014">{{cite journal|last1=Trotter|first1=Meredith V.|last2=Weissman |first2=Daniel B. |last3=Peterson |first3=Grant I. |last4=Peck|first4=Kayla M.|last5=Masel|first5=Joanna |author5-link=Joanna Masel|title=Cryptic genetic variation can make "irreducible complexity" a common mode of adaptation in sexual populations|journal=Evolution|date=December 2014|volume=68 |issue=12 |pages=3357–3367 |doi=10.1111/evo.12517 |pmid=25178652|pmc=4258170}}</ref> A number of mathematical models of evolution have explored the circumstances under which such valleys can, nevertheless, be crossed.<ref>{{cite journal|last1=Weissman|first1=Daniel B.|last2=Desai|first2=Michael M.|last3=Fisher|first3=Daniel S. |last4=Feldman |first4=Marcus W.|title=The rate at which asexual populations cross fitness valleys|journal=Theoretical Population Biology|date=June 2009 |volume=75 |issue=4|pages=286–300|doi=10.1016/j.tpb.2009.02.006|pmid=19285994|pmc=2992471}}</ref><ref>{{cite journal|last1=Weissman|first1=D. B.|last2=Feldman|first2=M. W. |last3=Fisher|first3=D. S. |title=The Rate of Fitness-Valley Crossing in Sexual Populations|journal=Genetics|date=5 October 2010|volume=186 |issue=4 |pages=1389–1410 |doi=10.1534/genetics.110.123240 |pmid=20923976|pmc=2998319}}</ref><ref name="trotter2014" /><ref>{{cite journal |last1=Covert|first1=Arthur|last2=Lenski |first2=Richard |last3=Wilke |first3=Claus |last4=Ofria |first4=Charles |title=Experiments on the role of deleterious mutations as stepping stones in adaptive evolution |journal=Proceedings of the National Academy of Sciences |date=2013|volume=110|issue=34|pages=E3171–E3178|doi=10.1073/pnas.1313424110|pmid=23918358|pmc=3752215|bibcode=2013PNAS..110E3171C|doi-access=free}}</ref>

An example of a structure that is claimed in Dembski's book ''No Free Lunch'' to be irreducibly complex, but evidently has evolved, is the protein T-urf13,<ref name="Wein 2002">{{cite web | last=Wein | first=Richard | title=Not a Free Lunch But a Box of Chocolates. A critique of William Dembski's book No Free Lunch| website=TalkOrigins Archive | date=23 April 2002 | url=http://www.talkorigins.org/design/faqs/nfl/#evid | access-date=25 August 2022|quote=Dembski considers the case of a gene, T-urf13, which occurs in a particular strain of maize ... Specified complexity (CSI) is not a marker of intelligent design. If specified complexity is determined according to the uniform-probability interpretation, then natural processes are perfectly capable of generating it. If it is determined by the chance-elimination method, then specified complexity is just a disguise for the god-of-the-gaps argument.}}</ref> which is responsible for the [[cytoplasmic male sterility]] of [[waxy corn]] and is due to a completely new gene.<ref>Levings 3rd, C.S. (1990) The Texas cytoplasm of maize: cytoplasmic male sterility and disease susceptibility. Science 250, 942–947.</ref> It arose from the fusion of several non-protein-coding fragments of mitochondrial DNA and the occurrence of several mutations, all of which were necessary. Behe's book ''Darwin Devolves'' claims that things like this would take billions of years and could not arise from random tinkering, but the corn was bred during the 20th century. When presented with T-urf13 as an example for the evolvability of irreducibly complex systems, the Discovery Institute resorted to its flawed probability argument based on false premises, akin to the [[Texas sharpshooter fallacy]].<ref>Andreas Beyer, Hansjörg Hemminger & Martin Neukamm: [https://www.ag-evolutionsbiologie.net/pdf/2022/evolution-of-t-urf13-irreducible-complexity.pdf The Evolution of T-URF13: Does Irreducible Complexity count or not?], and as [https://pandasthumb.org/archives/2022/06/evolution-of-t-urf13.html HTML document on the website of "Panda's Thumb".]</ref>