Editing Gregor Mendel (section)

==== Rediscovery of Mendel's work ====
About forty scientists listened to Mendel's two groundbreaking lectures, but it would appear that they failed to understand the implications of his work. Later, he also carried on a correspondence with [[Carl Nägeli]], one of the leading biologists of the time, but Nägeli also failed to appreciate Mendel's discoveries. At times, Mendel must have entertained doubts about his work, but not always: "My time will come," he reportedly told a friend,<ref name=":0" /> Gustav von Niessl.<ref name=":5">{{Cite journal|last=Gustafsson|first=A.|date=1969|title=The life of Gregor Johann Mendel--tragic or not?|journal=Hereditas|volume=62|issue=1|pages=239–258|doi=10.1111/j.1601-5223.1969.tb02232.x|pmid=4922561|doi-access=free}}</ref>

During Mendel's lifetime, most biologists held the idea that all characteristics were passed to the next generation through [[blending inheritance]] (indeed, many effectively are), in which the traits from each parent are averaged.<ref>{{Cite journal|last=Weldon|first=W. F. R.|date=1902|title=Mendel's Laws of Alternative Inheritance in Peas|url=https://academic.oup.com/biomet/article-lookup/doi/10.1093/biomet/1.2.228|journal=Biometrika|volume=1|issue=2|pages=228–233|doi=10.1093/biomet/1.2.228}}</ref><ref>{{Cite journal|last=Bulmer|first=Michael|date=1999|title=The Development of Francis Galton's Ideas on the Mechanism of Heredity|url=http://link.springer.com/10.1023/A:1004608217247|journal=Journal of the History of Biology|volume=32|issue=2|pages=263–292|doi=10.1023/A:1004608217247|pmid=11624207|s2cid=10451997}}</ref> Instances of this phenomenon are now explained by the action of multiple genes with [[Quantitative genetics|quantitative effects]]. Charles Darwin tried unsuccessfully to explain inheritance through a theory of [[pangenesis]]. It was not until the early 20th century that the importance of Mendel's ideas was realized.<ref name="Moore-2003" />

By 1900, research aimed at finding a successful theory of discontinuous inheritance rather than [[blending inheritance]] led to independent duplication of his work by [[Hugo de Vries]] and [[Carl Correns]] and the rediscovery of Mendel's writings and laws. Both acknowledged Mendel's priority, and it is thought probable that de Vries did not understand the results he had found until after reading Mendel.<ref name="Moore-2003" /> Though [[Erich von Tschermak]] was originally also credited with rediscovery, this is no longer accepted because he did not understand [[Mendelian inheritance|Mendel's laws]].<ref>{{cite book |author=Mayr E. |author-link=Ernst Mayr |year=1982 |title=The Growth of Biological Thought |location=Cambridge |publisher=The Belknap Press of Harvard University Press |isbn=978-0-674-36446-2 |page=730}}</ref> Though de Vries later lost interest in Mendelism, other biologists started to establish modern genetics as a science. All three of these researchers, each from a different country, published their rediscovery of Mendel's work within a two-month span in the spring of 1900.{{sfn|Henig|2000|pp=1–9}}

Mendel's results were quickly replicated, and genetic linkage quickly worked out. Biologists flocked to the theory; even though it was not yet applicable to many phenomena, it sought to give a [[genotype|genotypic]] understanding of heredity, which they felt was lacking in previous studies of heredity, which had focused on [[phenotype|phenotypic]] approaches.<ref>{{Cite book|title=Mendel's Legacy: The Origins of Classical Genetics|last=Carlson|first=Elof Axel|publisher=Cold Spring Harbor|year=2004|location=New York}}</ref> Most prominent of these previous approaches was the [[Biostatistics|biometric]] school of [[Karl Pearson]] and [[W. F. R. Weldon]], which was based heavily on statistical studies of phenotype variation. The strongest opposition to this school came from [[William Bateson]], who perhaps did the most in the early days of publicising the benefits of Mendel's theory (the word "[[genetics]]", and much of the discipline's other terminology, originated with Bateson). This debate between the biometricians and the Mendelians was extremely vigorous in the first two decades of the 20th century, with the biometricians claiming statistical and mathematical rigor,<ref>{{cite journal|last1=Deichmann|first1=Ute|title=Early 20th-century research at the interfaces of genetics, development, and evolution: Reflections on progress and dead ends|journal=Developmental Biology|date=2011|volume=357|issue=1|pages=3–12|doi=10.1016/j.ydbio.2011.02.020 |pmid=21392502|doi-access=free}}</ref> whereas the Mendelians claimed a better understanding of biology.<ref>{{cite journal|last1=Elston|first1=RC|last2=Thompson|first2=EA|author2-link= Elizabeth A. Thompson |title=A century of biometrical genetics|journal=Biometrics|date=2000|volume=56|issue=3|pages=659–66|pmid=10985200|doi=10.1111/j.0006-341x.2000.00659.x|s2cid=45142547}}</ref><ref>{{cite journal|last1=Pilpel|first1=Avital|title=Statistics is not enough: revisiting Ronald A. Fisher's critique (1936) of Mendel's experimental results (1866)|journal=Studies in History and Philosophy of Science Part C: Studies in History and Philosophy of Biological and Biomedical Sciences|date=September 2007|volume=38|issue=3|pages=618–26|doi=10.1016/j.shpsc.2007.06.009 |pmid=17893069}}</ref> Modern genetics shows that Mendelian heredity is, in fact, an inherently biological process, though not all genes of Mendel's experiments are yet understood.<ref>{{Cite journal|last1=Reid|first1=J. B.|last2=Ross|first2=J. J.|title=Mendel's genes: toward a full molecular characterization|journal=Genetics|date=2011|volume=189|issue=1|pages=3–10|doi=10.1534/genetics.111.132118|pmid=21908742|pmc=3176118}}</ref><ref>{{cite journal|last1=Ellis|first1=T.H. Noel|last2=Hofer|first2=Julie M.I.|last3=Timmerman-Vaughan|first3=Gail M.|last4=Coyne|first4=Clarice J.|last5=Hellens|first5=Roger P.|title=Mendel, 150 years on|journal=Trends in Plant Science|date=2011|volume=16|issue=11|pages=590–96|doi=10.1016/j.tplants.2011.06.006|pmid=21775188|bibcode=2011TPS....16..590E }}</ref>

Ultimately, the two approaches were combined, especially by work conducted by [[R. A. Fisher]] as early as 1918. The combination, in the 1930s and 1940s, of Mendelian genetics with Darwin's theory of [[natural selection]] resulted in the [[Modern synthesis (20th century)|modern synthesis]] of [[evolutionary biology]].<ref>{{cite journal|last1=Kutschera |first1=Ulrich|last2=Niklas|first2=KarlJ.|title=The modern theory of biological evolution: an expanded synthesis|journal=Naturwissenschaften|date=2004|volume=91|issue=6|pages=255–76|doi=10.1007/s00114-004-0515-y|pmid=15241603|bibcode=2004NW.....91..255K|s2cid=10731711}}</ref><ref>{{cite book|last1=Hall|first1=Brian Keith|last2=Hallgrímsson|first2=Benedikt|last3=Strickberger |first3=Monroe W.|title=Strickberger's evolution|date=2014|publisher=Jones & Bartlett Learning|location=Burlington, Mass.|isbn=978-1-4496-1484-3|pages=10–11|edition=5|url=https://books.google.com/books?id=WkcvuVpzjYQC}}</ref>

In the [[Soviet Union]] and China, Mendelian genetics was rejected in favor of [[Lamarckism]], leading to imprisonment and even execution of Mendelian geneticists (see [[Lysenkoism]]).