Editing Chromosome (section)

== History of discovery ==
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| footer = [[Walter Sutton]] (left) and [[Theodor Boveri]] (right) independently developed the chromosome theory of inheritance in 1902.
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[[Otto Bütschli]] was the first scientist to recognize the structures now known as chromosomes.<ref>{{cite journal | vauthors = Fokin SI | year = 2013 | title = Otto Bütschli (1848–1920) Where we will genuflect? | url=https://www.zin.ru/journals/protistology/num8_1/fokin_protistology_8-1.pdf | journal = Protistology | volume = 8 | issue = 1 | pages = 22–35 | url-status = dead |archive-url = https://web.archive.org/web/20210421055737/https://www.zin.ru/journals/protistology/num8_1/fokin_protistology_8-1.pdf |archive-date = 21 April 2021}}</ref>

In a series of experiments beginning in the mid-1880s, [[Theodor Boveri]] gave definitive contributions to elucidating that chromosomes are the [[Vector (molecular biology)|vectors]] of [[heredity]], with two notions that became known as 'chromosome continuity' and 'chromosome individuality'.<ref>{{Cite journal|last=Maderspacher|first=Florian|year=2008|title=Theodor Boveri and the natural experiment|journal=Current Biology|volume=18|issue=7|pages=R279–R286|doi=10.1016/j.cub.2008.02.061|pmid=18397731|s2cid=15479331|doi-access=free|bibcode=2008CBio...18.R279M }}</ref>

[[Wilhelm Roux]] suggested that every chromosome carries a different [[Genetic load|genetic configuration]], and Boveri was able to test and confirm this hypothesis. Aided by the rediscovery at the start of the 1900s of [[Gregor Mendel]]'s earlier experimental work, Boveri identified the connection between the rules of inheritance and the behaviour of the chromosomes. Two generations of American [[cytologist]]s were influenced by Boveri: [[Edmund Beecher Wilson]], [[Nettie Stevens]], [[Walter Sutton]] and [[Theophilus Painter]] (Wilson, Stevens, and Painter actually worked with him).<ref>{{cite book | last = Carlson | first = Elof A. | title = Mendel's Legacy: The Origin of Classical Genetics | location = Cold Spring Harbor, NY | publisher = Cold Spring Harbor Laboratory Press | pages = 88 | year = 2004 | isbn = 978-087969675-7 | url = http://www.cshlpress.com/pdf/sample/mendel7.pdf }}</ref>

In his famous textbook, ''The Cell in Development and Heredity'', Wilson linked together the independent work of Boveri and Sutton (both around 1902) by naming the chromosome theory of inheritance the '[[Boveri–Sutton chromosome theory]]' (sometimes known as the 'Sutton–Boveri chromosome theory').<ref>Wilson, E.B. (1925). ''The Cell in Development and Heredity'', Ed. 3. Macmillan, New York. p. 923.</ref> [[Ernst Mayr]] remarks that the theory was hotly contested by some famous geneticists, including [[William Bateson]], [[Wilhelm Johannsen]], [[Richard Goldschmidt]] and [[T.H. Morgan]], all of a rather dogmatic mindset. Eventually, absolute proof came from chromosome maps in Morgan's own laboratory.<ref>Mayr, E. (1982). ''The growth of biological thought''. Harvard. p. 749. {{ISBN|9780674364462}}</ref>

The number of human chromosomes was published by Painter in 1923. By inspection through a microscope, he counted 24 pairs of chromosomes, giving 48 in total. His error was copied by others, and it was not until 1956 that the true number (46) was determined by Indonesian-born [[cytogeneticist]] [[Joe Hin Tjio]].<ref>{{Cite journal|last=Gartler|first=Stanley M.|date=1 August 2006|title=The chromosome number in humans: a brief history|journal=Nature Reviews Genetics|volume=7|issue=8 |pages=655–660|doi=10.1038/nrg1917|pmid=16847465 |s2cid=21365693 }}</ref>