Editing J. B. S. Haldane (section)

=== Population genetics ===
{{further|Modern synthesis (20th century)}}

Haldane was one of the three major figures to develop the mathematical theory of [[population genetics]], along with [[Ronald Fisher]] and [[Sewall Wright]]. He thus played an important role in the [[modern synthesis (20th century)|modern evolutionary synthesis]] of the early 20th century. He re-established [[natural selection]] as the central mechanism of [[evolution]] by explaining it as a mathematical consequence of [[Mendelian inheritance]].<ref>{{cite journal|last=Haldane|first=JB|year=1990|title=A mathematical theory of natural and artificial selection—I. 1924|journal=Bulletin of Mathematical Biology|volume=52|issue=1–2|pages=209–40; discussion 201–7|doi=10.1007/BF02459574|pmid=2185859|s2cid=189884360}}</ref><ref>{{cite journal|last=Haldane|first=JB|year=1959|title=The theory of natural selection today|journal=Nature|volume=183|issue=4663|pages=710–3|bibcode=1959Natur.183..710H|doi=10.1038/183710a0|pmid=13644170|s2cid=4185793}}</ref> He wrote a series of ten papers, [[A Mathematical Theory of Natural and Artificial Selection]], deriving expressions for the direction and rate of change of [[gene frequencies]], and also analyzing the interaction of natural selection with [[mutation]] and [[migration (ecology)|migration]]. The series consists of ten papers published between 1924 and 1934 in journals such as ''[[Biological Reviews]]'' (part II), ''[[Mathematical Proceedings of the Cambridge Philosophical Society]]'' (parts I and from III to IX), and ''[[Genetics (journal)|Genetics]]'' (part X).<ref name=":10">{{Cite journal|last=Haldane|first=J. B. S.|date=1990|orig-year=1924|title=A mathematical theory of natural and artificial selection—I|url=https://www.blackwellpublishing.com/ridley/classictexts/haldane1.pdf|journal=Bulletin of Mathematical Biology|language=en|volume=52|issue=1–2|pages=209–240|doi=10.1007/BF02459574|pmid=2185859|s2cid=189884360}}</ref><ref>{{Cite journal|last=Haldane|first=J. B.|date=1934|title=A Mathematical Theory of Natural and Artificial Selection Part X. Some Theorems on Artificial Selection|journal=Genetics|volume=19|issue=5|pages=412–429|doi=10.1093/genetics/19.5.412|pmc=1208491|pmid=17246731}}</ref><ref>{{Cite journal|last=Bodmer|first=W. F.|date=2017|title=A Haldane perspective from a Fisher student|url=http://link.springer.com/10.1007/s12041-017-0825-4|journal=Journal of Genetics|language=en|volume=96|issue=5|pages=743–746|doi=10.1007/s12041-017-0825-4|pmid=29237882|s2cid=33409033}}</ref> He gave a set of lectures based on this series at the [[University of Wales]] in 1931, and they were summarised in his book, ''[[The Causes of Evolution]]'' in 1932.<ref name=":9">{{Citation|last=Sarkar|first=Sahotra|title=Haldane as Biochemist: The Cambridge Decade, 1923–1932|date=1992|url=http://link.springer.com/10.1007/978-94-011-2856-8_4|work=The Founders of Evolutionary Genetics|series=Boston Studies in the Philosophy of Science|volume=142|pages=53–81|editor-last=Sarkar|editor-first=Sahotra|place=Dordrecht|publisher=Springer Netherlands|doi=10.1007/978-94-011-2856-8_4|isbn=978-0-7923-3392-0|access-date=7 August 2021}}</ref>

His first paper on the series in 1924 specifically deals with the rate of natural selection in [[peppered moth evolution]]. He predicted that environmental conditions can favour the increase or decline of either the dominant (in this case the black or [[Melanism|melanic forms]]) or the recessive (the grey or [[wild type]]) moths. For a sooty environment such as Manchester, where the phenomenon was discovered in 1848, he predicted that the "fertility of the dominants must be 50% greater than that of the recessives".<ref name=cook50/> According to his estimate, assuming 1% dominant form in 1848 and about 99% in 1898, "48 generations are needed for the change [for the dominant to appear]... After only 13 generations the dominants would be in a majority."<ref name=":10" /> Such mathematical prediction was considered improbable for natural selection in nature,<ref name=":8" /> but it was subsequently proven by an elaborate experiment (named [[Kettlewell's experiment]]) that was performed by an Oxford zoologist [[Bernard Kettlewell]] between 1953 and 1958.<ref name="kett1955">{{cite journal|last1=Kettlewell|first1=H B D|year=1955|title=Selection experiments on industrial melanism in the Lepidoptera|journal=Heredity|volume=9|issue=3|pages=323–342|doi=10.1038/hdy.1955.36|doi-access=free|bibcode=1955Hered...9..323K }}</ref><ref name="kett56">{{cite journal|last1=Kettlewell|first1=Bernard|year=1956|title=Further selection experiments on industrial melanism in the Lepidoptera|journal=Heredity|volume=10|issue=3|pages=287–301|doi=10.1038/hdy.1956.28|doi-access=free|bibcode=1956Hered..10..287K |authorlink=Bernard Kettlewell}}</ref><ref name="kett58">{{cite journal|last1=Kettlewell|first1=Bernard|year=1958|title=A survey of the frequencies of ''Biston betularia'' (L.) (Lep.) and its melanic forms in Great Britain|journal=Heredity|volume=12|issue=1|pages=51–72|doi=10.1038/hdy.1958.4|doi-access=free|bibcode=1958Hered..12...51K |authorlink=Bernard Kettlewell}}</ref> Haldane's prediction was proven further by a Cambridge geneticist [[Michael Majerus]] in his experiments conducted between 2001 and 2007.<ref name="Cook2012">{{cite journal|author=Cook, L. M.|author2=Grant, B. S.|author3=Saccheri, I. J.|author4=Mallet, James|year=2012|title=Selective bird predation on the peppered moth: the last experiment of Michael Majerus|journal=Biology Letters|volume=8|issue=4|pages=609–612|doi=10.1098/rsbl.2011.1136|pmc=3391436|pmid=22319093}}</ref>

His contributions to statistical human genetics included: the first methods using [[maximum likelihood]] for the estimation of human [[linkage map]]s; pioneering methods for estimating human mutation rates; the first estimates of [[rate of mutation|mutation rate]] in humans (2 × 10<sup>−5</sup> mutations per gene per generation for the X-linked [[haemophilia]] [[gene]]); and the first notion that there is a "cost of natural selection".<ref>{{cite journal|last=Haldane|first=J. B. S.|year=1935|title=The rate of spontaneous mutation of a human gene|journal=Journal of Genetics|volume=31|issue=3|pages=317–326|doi=10.1007/BF02982403|s2cid=34797487}}</ref> He was the first to estimate the rate of human mutation in his 1932 book entitled ''The Causes of Evolution''.<ref>{{Cite journal|last=Nachman|first=Michael W.|date=2004|title=Haldane and the first estimates of the human mutation rate|journal=Journal of Genetics|volume=83|issue=3|pages=231–233|doi=10.1007/BF02717891|pmid=15689624|doi-access=free}}</ref> At the [[John Innes Horticultural Institution]], he developed the complicated linkage theory for polyploids;<ref name="jic.ac.uk" /><ref>{{Cite journal|last=Haldane|first=J. B. S.|date=1930|title=Theoretical genetics of autopolyploids|url=http://link.springer.com/10.1007/BF02984197|journal=Journal of Genetics|language=en|volume=22|issue=3|pages=359–372|doi=10.1007/BF02984197|s2cid=46262752}}</ref> and extended the idea of gene-enzyme relationships with the biochemical and genetic study of plant pigments.<ref>{{Cite journal|last=Crow|first=James F.|date=1985|title=JBS Haldane-an appreciation|url=http://link.springer.com/10.1007/BF02923548|journal=Journal of Genetics|language=en|volume=64|issue=1|pages=3–5|doi=10.1007/BF02923548|s2cid=34693589}}</ref><ref name=":3" />