Gregor Mendel

[[File:Gregor Mendel.png|thumb|right|165px||Bless you!]]
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'''Gregor Mendel''' {{lived|July 20, 1822|January 6, 1884}} was a Augustinian, Christian friar and abbot, teacher, and pioneer in the field of [[genetics]]. He was born into a German-speaking family in Silesia (then part of the [[Austria|Austrian Empire]], now the [[Czech Republic]]), he discovered the basic laws of heredity using pea plants and introduced a quantitative, experimental approach to biology that was decades ahead of its time. In 1865, he presented his groundbreaking paper on inheritance (''{{wpl|Experiments on Plant Hybridization}}''), but his [[scientific]] work was curtailed when he became abbot of his monastery and took on increasingly demanding administrative duties. Contrary to popular myths, Mendel's work was not ignored because he was a monk. Rather, the scientific community of his day favored descriptive {{wpl|natural history}} over [[mathematics]], and his ideas conflicted with the prevailing notion of {{wpl|blending inheritance||.}}<ref>[http://www.mendelweb.org/MWGerText.html Versuche über Pflanzen-Hybriden] by Gregor Mendel (1865) Verhandlungen des naturforschenden Vereines in Brünn, Band 4, pp. 3-47.</ref><ref>{{cite web |author=Robert Olby & Britannica Editors |date= January 2, 2026 |title= Gregor Mendel |url= https://www.britannica.com/biography/Gregor-Mendel|website= Encyclopædia Britannica |access-date=January 20, 2026}}</ref><ref>{{cite journal |author=Editiorial |date= July 19, 2022 |title=The true legacy of Gregor Mendel: careful, rigorous and humble science |url=https://www.nature.com/articles/d41586-022-01953-z |journal= Nature|volume= |issue= 607 |doi= https://doi.org/10.1038/d41586-022-01953-z |access-date=January 20, 2026}}</ref><ref>{{cite web |last= Jayaswal|first= Shakuntala|date=2023 |title=Gregor Mendel |url=https://www.ebsco.com/research-starters/history/gregor-mendel |website=EBSCO Knowledge Advantage |access-date=January 20, 2026}}</ref>

Mendel’s findings were largely forgotten until around 1900 - well after his [[death]] - when {{wpl|Hugo de Vries||,}} {{wpl|Carl Correns||,}} and {{wpl|Erich von Tschermak}} independently "rediscovered" his laws of inheritance. Mendel’s results were remarkably close to theoretical expectations, which has led some historians and statisticians to debate whether he may have subconsciously adjusted or rounded his data. While this debate continues, there is no consensus that he intentionally falsified anything. Although Mendelian inheritance is simple to state, real genetics is far more complex. Phenomena such as ''incomplete dominance'', ''polygenic traits'', ''epigenetics'', and other interactions were not observed by Mendel, but they are common in actual biological systems.<ref>Das, S.S. Mendel paved the path toward understanding genetic diseases. Egypt J Med Hum Genet 23, 124 (2022). https://doi.org/10.1186/s43042-022-00339-0</ref><ref>Radick, G (2022) Mendel the fraud? A social history of truth in genetics. Studies in History and Philosophy of Science, 93. pp. 39-46. ISSN 0039-3681</ref><ref>Fairbanks DJ, Rytting B. Mendelian controversies: a botanical and historical review. Am J Bot. 2001 May;88(5):737-52. PMID: 11353700.</ref><ref>Wolf, J.B., Ferguson-Smith, A.C. & Lorenz, A. Mendel’s laws of heredity on his 200th birthday: What have we learned by considering exceptions?. Heredity 129, 1–3 (2022). https://doi.org/10.1038/s41437-022-00552-y</ref>

==Mendelian genetics==
[[File:Punnett square mendel flowers.svg|thumb|left|150px|The {{wpl|Punnett square}} (devised by {{wpl|Reginald C. Punnett}}) provides a visual representation of Mendelian inheritance.]]
Through [[experiment]]ation on peas, Mendel demonstrated several properties of inherited traits. He postulated that traits are determined by [[gene]] pairs. An organism's outward appearance, or [[phenotype]], is dictated by the alternative forms, or [[allele]]s, of genes in the pair. Given a dominant allele D and a recessive allele r, the possible gene pairs are DD, Dr and rr. The recessive allele then is present in all but the first case, although the recessive trait will be expressed only in the last case.

Mendel further postulated that an organism's genetic makeup, or genotype, is inherited. He noted that, for each trait, the gene pair is formed by the receipt of one allele from each parent. This observation is identified as the Law of Segregation, or Mendel's First Law. He also noted that the combination of alleles inherited for a given trait is independent of that for other traits. This observation is identified as the Law of Independent Assortment, or Mendel's Second Law.

Mendel choosing peas as his model organism was one of those moments when science got lucky. Peas have multiple traits controlled by only a single gene in what is termed 'complete dominance' (where the dominant allele completely masks the recessive allele if both are present, as above). In most organisms, things get a lot more complicated and difficult to sort out very quickly due to factors such as polygenic traits (multiple different genes affect the same trait), pleiotropy (one gene affects multiple traits), co-dominance or incomplete dominance (where two different alleles don't behave dominantly or submissively with respect to each other but compromise), [[Chromosome|chromosomal]] linkage which causes traits to apparently break the Second Law… You get the picture. Just take eye colour. Eye colour is controlled by two genes, OCA2 and Gey, making it polygenic, but it's also a case of incomplete dominance, meaning that it's ''really'' hard to study. Basically, [[Pokémon|Mendel accidentally chose a Caterpie instead of an Eevee.]]

==External links==
*[http://www.mendelweb.org/Mendel.html Mendel's Paper in English], MendelWeb
*{{wpa|Gregor Mendel}}
*{{wpa|Mendelian inheritance}}

==References==
{{reflist|2|80%}}

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[[Category:Scientists]]
[[Category:Genetics]]
[[Category:Christians]]

Categories: Scientists, Genetics, Christians