Carl Friedrich Gauss: (1777, Brauschweig - 1855, Göttingen)

高斯 數學是科學的皇后 狐狸的足跡

生命綿延的數學性 : 另一種思維習慣

( 德語世界的科學事件之一 )

1

楊倍昌

中國和西方的科技在 1450 年到 1600 年間仍有並駕齊驅的樣子，之後西歐突出，才使中國望塵莫及。 ? ( 李約瑟難題 )

黃仁宇轉述李約瑟的話 , in: 放寬歷史的視界 1988, 允晨叢刊、台北 , p:94

中國一百年來的革命，已於 1980 年代完成。期間最大的一個收穫，則是今後這個國家已能在數目字上管理 (mathematically manageable) 。

黃仁宇 : 放寬歷史的視界 1988, 允晨叢刊、台北 , p142

是嗎 ? (BC)

2

Johann MENDEL (der Vorname Gregor wurde ihm nach seinem Eintritt ins Kloster verliehen), geb. 1822 in Heinzendorf (im deutschen Teil des damals österreichischen Schlesiens), Abt in Brünn, gest. 1884, publizierte 1866 (?) eine zwar kleine aber inhaltsschwere Schrift mit dem Titel “VERSUCHE ÜBER PFLANZEN-HYBRIDEN.

3

http://www.mendel-museum.org/

http://www.mendelweb.org/MWtoc.html

資料很完整的網站 :

4

In the Footsteps of Mendelby Margaret Hermánek Peaslee

Professor of Biology and Vice President for Academic AffairsUniversity of Pittsburgh at Titusville

http://www.mendelweb.org/MWpeaslee.html

5

在孟德爾的花園裡

他想要回答什麼問題 ?

為什麼結果被埋沒近 (35) 年 ?

是什麼認知環境，讓後人了解到孟德爾研究的重要性 ?

 "gelb x gelb = grün ...wenigstens manchmal"

1865+35=1900

6

很完整的討論 : http://www.weloennig.de/mendel.htm

Warum seine Entdeckungen 35 (72?) Jahre ignoriert wurden Ein paar kritische Kommentare von Pionieren der Genetik

sowie weiteren Biologen und Biologiehistorikern zur Wirkung des Darwinismus auf die biologische Forschung

Why his discoveries were ignored for 35 (72) years Some critical comments about the effects of Darwinism

on Biological Research by Pioneers of Genetics as well as further Biologists and Historians of Biology (German with English Summary)

7

http://www.weloennig.de/mendel.htm

After two lectures in 1865, Mendel published his famous Pisum-treatise

VERSUCHE ÜBER PFLANZEN-HYBRIDEN in 1866. His work was

quoted at least 14 times before 1900, the year of its 'rediscovery'. There

were references in such widely distributed works as Focke's DIE

PFLANZEN-MISCHLINGE (1881), THE ENCYCLOPAEDIA

BRITANNICA (1881) and the CATALOGUE OF SCIENTIFIC PAPERS

OF THE ROYAL SOCIETY (1879). The treatise had been sent to the

libraries of some 120 institutions including the Royal and Linnean Society

of Great Britain. Moreover Mendel had 40 additional reprints at his

disposal, many of which he sent to leading biologists of Europe. In fact,

professor Niessl (1903 and 1906) emphasized that Mendel's work was

"well known" at his time.

8

是什麼東西引起孟德爾如此大的興趣，讓他願意花費八 (?) 年時間進行植物雜交實驗 ?

在費曼之前 – 二十世紀的科學簡史 ; 陳恒安譯 , 究竟 , 台北 (2002).

Ernst Peter Fischer (1995), Einstein & Co.: Eine kleine Geschichte der Wissenschaft der letzten hundert Jahre in Porträts.

或者他只是無聊找事做 ?

9

Which date is correct?

1865, Mendel gave Lectures on “Experiments in Plant Hybrids” at the February and March meetings of the Natural Science Society (Brno).

Vorgelegt in den Sitzungen vom 8. Februar und 8. März 1865) ; 9. Februar in Brünner Tagblatt.

1866, Mendel published his lecture, a work that was to establish him as “the father of genetics”.

Versuche über Pflanzen-Hybriden, in Verhandlungen des naturforschenden Vereins Brünn 4, 3 -47 (Nachruck; Weinheim 1960).

http://www.mendelweb.org/MWGerText.htmlhttp://www.weloennig.de/mendel.htm

10

Why to say after 72 years?

• Fisher RA (1936), a mathematically inclined scientist, was to deal with the problem of Mendel’s data being “too good”, it is impossible to him that the expected and actual data could be so similar.

• In the case of the yellow x green: The total number of seeds scored was 179,399. Of these, 134,707 were yellow (75.08796 percent) and 44,692 were green (24.91206). Mendel had reported 75.05% vs 24.95%.

Fisher, R.A. (1936). Has Mendel's Work Been Rediscovered? Annals of Science 1, 115-137.

11

In 1807, an imperial order demanded that the Augustinians at St Thomas should take up the teaching of mathematics and biblical studies in the newly established Philosophy Institute and the Brno Theology College.

Flood and other presumed catastrophes receded, first in the face of Scottish geologist Charles Lyell's arguments begun in the 1830s that the Earth had been shaped by gradual, ordinary forces working over a vast timescale. They ebbed even further with the coming of Darwinism in the 1860s (against the biblical answer ).

孟德爾是修士、學過物理、數學、生物學

12

A link between the study of natural disciplines, such as botany and zoology, and physics had already been expressed by Andreas Baumgartner (1793-1865), professor of Physics at the University of Vienna until 1864, who acted as examiner for Mendel in Brno in 1850. Baumgartner had been so impressed by Mendel, that he suggested to Abbot Napp that the young monk should be sent to the University of Vienna. Professor Baumgartner emphasized the importance of studying nature, not through random speculation but through experiments theoretically underpinned by mathematical models.

13

Andreas Baumgartner (1793 - 1865) In 1823 he lectured at

Vienna university, published his works as well as a Magazine of physics and mathematics, and wrote a book of elementary physics.

A native of  Frymburk in the Český Krumlov region.

孟德爾的老師

14

孟德爾的老師 Franz Unger (1800-1870) : about

Evolution (1852, Wien), test how variation is formed (How to do this?).

Darwin published “On the origin of species: in 1859

1869, Mendel had talked about evolution, and sent a copy of paper to Darwin.

Christian Doppler (1803-1853 ): on physics.

15

16

17

http://www.gmi.oeaw.ac.at/institut2geschichte.htm18

孟德爾還知道哪些事 ?

Atomic theory by John Dalton (1766-1844).

可能知道 Statistic 嗎 ?

http://falcon.sbuniv.edu/~ggray.wh.bol/CHE1104/pcp3outl.html

Father of epidemiology: John Snow: 1813-1859

19

Mendel's green pea (Pisum sativum), is also called the garden pea or English pea.

20

http://ridge.icu.ac.jp/gen-ed/mendel-gifs/18-mendel-cartoon.JPGhttp://www.brooklyn.cuny.edu/bc/ahp/MBG/MBG.Peas.html

• The monks in Mendel's

monastery would have

really appreciated his

crops as peas are best if

eaten almost

immediately. Like corn,

peas lose their sweet

flavor very rapidly.

21

A. List of seeds ordered by Mendel to Ernst Benary for the Abbey, 2nd November 1878, and a bill from the seed firm, Bestell Nota Herrn Ernst Benary in Erfurt.Brno, Abbey of St Thomas

B. Grafting and pruning tools in wooden box, Dittmar Keilbronn Brno, Abbey of St Thomas

A B

孟德爾用的工具吧

http://www.mendel-museum.org/eng/1online/room1.htm

22

香豌豆 Lathyrus odoratus L.

• 別名：花豌豆、麝香豌豆、香豆花• 一、二年生草本；莖有翅，被短柔毛，柔軟多汁，高約 150 公分左右。葉為羽狀複葉，寬橢圓形或長圓狀卵形，葉基的一、二小葉先變為卷鬚，可捲繞它物而向上生長；葉軸有翅，上部有 3-5 對卷鬚。總狀花序有花 1-5 朵，蝶形花冠有白、紅、粉紅、紫紅等多種顏色，具香氣。莢果有短柔毛；種子多數，近球形，熟時灰棕色。花果期 4-9 月。• 有毒部位：種子和開花時期的莖、葉有毒，以未成熟種子毒性最強。中毒病狀：人中毒後往往出現一系列脊椎功能障礙，開始時兩腿無力，然後腰痛逐漸加重，行走困難，前進時足向內翻或貼地。

不要與觀賞用的香豌豆混淆了

23

Mendel‘s green pea ( 這不是一開始的說法 )

D R D R

Seed shape

Seed color

Flower color

Pot color

Pot shape

Stem high

Flower position

http://ridge.icu.ac.jp/gen-ed/mendel-gifs/03-mendel-characters2.JPG

應該是子葉的顏色

24

孟德爾用的七種豌豆特徵1. Shape of seed, whether rounded or irregularly angular and deeply

wrinkled.

2. Colour of cotyledons [“ endosperm”], whether some shade of yellow or green.

3. Colour of seed-skin, whether a brownish shade or white (in correlation with white flowers).

4. Shape of ripe pod, whether simply inflated or deeply constricted between the seeds.

5. Colour of unripe pod, whether a shade of green or bright yellow.

6. Position of flowers, whether distributed along the stem or crowded near the top in a false umbel.

7. Length of stem, whether about 6-7 feet or about 3/4 --> 1 and 1/2 feet. Between these various pairs of varieties crosses were then made, the female parent being emasculated.

http://post.queensu.ca/~forsdyke/bateson1.htm

25

http://www.mendelweb.org/MWGerText.html德文版原文的記載

Auf den Unterschied in der Gestalt der reifen Samen. Auf den Unterschied in der Färbung des Samen-Albumens

[Endosperms]. Auf den Unterschied in der Färbung der Samenschale. Auf den Unterschied in der Form der reifen Hülse. Auf den Unterschied in der Farbe der unreifen Hülse. Auf den Unterschied in der Stellung der Blüthen. Auf den Unterschied in der Axenlänge.

For lecture only; BC Yang26

就是這樣做So ist es gemacht!

For lecture only; BC Yang

http://www.giddings.txed.net/biology/ch12.html

27

Mendelregeln 1. Uniformitätsregel (顯隱律 ):

– Kreuzt man zwei Individuen einer Art, die sich nur in einem Merkmal unterscheiden und in Bezug auf dasselbe homozygot sind, so sind die Individuen der Tochtergeneration (F1) im betrachteten Merkmal gleich, d.h. uniform. Alle Individuen der Tochtergeneration haben nicht nur denselben Phänotypus, sondern auch denselben Genotypus. Dies trifft sowohl beim intermediären als auch beim dominanten Erbgang zu.

2. Spaltungsregel (分離律 ):– Kreuzt man Individuen der F1- Generation unter sich weiter, so kommt es zu

einem Aufspalten der Merkmale. Vom Phänotypus findet das Aufspalten beim intermediären Erbgang im Verhältnis 1:2:1 statt, beim dominanten im Verhältnis 1:3. Der Genotypus tritt in beiden Erbgängen im Verhältnis 1:2:1 auf.

3. Regel von der Unabhängigkeit der Erbanlagen (獨立分配律 ):– Kreuzt man zwei Individuen einer Art, die sich in zwei Merkmalen

unterscheiden und in Bezug auf dieselben homozygot sind, so findet man in der F2- Generation eine Aufspaltung der Merkmale im Verhältnis 9:3:3:1 beim dominanten Erbgang. Dies beweist, dass die Gene unabhängig voneinander vererbt werden und frei kombinierbar sind.

28

由種子商購買 34 個豌豆品種，培育兩年成為純系。他發現有 22 株系的性狀穩定，然後又選定 7 種性狀作為觀察性狀在世代間傳遞情況的指標 .......

豌豆有七條染色體。 據說研究進行八年，對兩萬八千株植物進

行交配實驗。這八年孟德爾在想什麼 ?

在費曼之前 – 二十世紀的科學簡史 ; 陳恒安譯 , 究竟 , 台北 (2002), p 70. 原始資料待查 !

29

As time goes by, the biological life goes down to a sign of sign, a mix of molecules, and imaging

set of colors with colorless.

Mitosis in Onion Root Tips

Down to a microarray

具象與抽象

For lecture only; BC Yang30

在接受且理解孟德爾發現的必要條件有哪些 ?

孟德爾以概念 ( 以 Elementet 稱呼他所追蹤的遺傳

單位 ) 和假設的理論掌握自然的規律 ( 關係 ) 。但是概念必須有實物相對應，才能展現其存在的意義。

31

三個爭奪「重新」發現遺傳定律的故事

32

1. Hugo de Vries (1848-1935)

2. Carl Erich Correns (1864-1933)

3. Erich von Tschermak-Seysenegg (1871 -1962))

When Mendel's paper was published, in 1866, it received little attention, and was rarely cited by botanists or biologists during the next 34 years. Mendel's work has been thought to exemplify everything from the failure of traditional modes of scientific communication (Bush [1945]) to the phenomenon of "premature scientific discovery" ( Stent [1978]). In 1900, Mendel's work was cited by three botanists, writing in different parts of Europe: Hugo de Vries, in Amsterdam; Carl Correns, in Tübingen; and Eric Von Tcshermak, in Esslingen, Austria. Although their interpretations of what Mendel had shown were arguably inaccurate, these citations caused what has come to be known as the "rediscovery" of Mendel.

http://www.mendelweb.org/MWhartl.intro.html

33

It may be premised that the first publication of the re-discovery was made in 1900 by de Vries, {De Vries, 'Comptes Rendus,' March 26, 1900, and 'Ber. deut. Bot. Ges.,' xviii, 1900, p. 83; ibid., p. 435; 'Rev. gen. Bot.,' 1900, p. 257.} and almost simultaneously by Correns {Correns, 'Ber. deut. Bot. Ges.,' xviii, 1900, p. 158; 'Bot. Ztg.,' 1900, p. 232.} and Tschermak {Tschermak, 'Ztschr. f. d. landw. Versuchswesen in Oesterr.,' 1900, 3, p. 465}. There can be no doubt that the appearance of this group of papers constitutes at length a definite advance both in the general study of the physiology of reproduction and in the particular problem of the nature of Species.

http://post.queensu.ca/~forsdyke/bateson1.htm

34

Two stories A fellow Dutch scientist, Professor Beyerinck of Delft, knew that de

Vries had been hybridizing plants and wrote asking if he would be interested in an old reprint dealing with the same subject. It was Mendel’s “Versuche über Pflanzen Hybriden”, which reached de Vries in 1990, just as he was preparing to publish his own experiments.

In the autumn of 1899 the solution came to Correns in a “blind flash”, which seems to be the origin of the truly important breakthroughs in science. A short time later he found a reference to Mendel’s paper and looked it up. He published his own data and showed how it confirmed what Mendel had found.

Summary by Moore JA, 1993, in: Science as a way of Knowing, The foundations of modern biology. p286Moore 也把 Eric Von Tcshermak 的貢獻忽略了 !

35

Vries, Hugo de. "Das Spaltungsgesetz der Bastarde," Berichte der deutschen botanischen Gesellschaft 18 (1900), pp. 83-90. An English translation by Evelyn Stern, "The Law of Segregation of Hybrids", appears in Stern and Sherwood (1966), pp. 107-117.

Stern, Curt and Eva R. Sherwood ed. The Origin of Genetics: A Mendel Source Book. (W.H. Freeman and Company, 1966).

Hugo de Vries 1848-1935

36

De Vries { C. R., 1900, March 26; 'Ber. deut. Bot. Ges.,' 18, 1900, p. 83.} working with pairs of varieties belonging to a diversity of genera and species, found that in a large number of cases one of the varietal characters was definitely dominant, prevailing in the first crosses to the exclusion of the recessive character.

The offspring of the cross-breds fertilised inter se were mixed dominants and recessives in proportions fairly agreeing with Mendel's law.

In the case of two colour varieties of Papaver somniferum, the constitution of the resulting dominants was investigated, and shown to be also according to the law. In certain cases also the purity of the recessives was tested and found to be complete.

Papaver somniferum

罌粟

http://post.queensu.ca/~forsdyke/bateson1.htm37

在 Amsterdam 的旅館

Park Hotel "Hugo de Vries" is gehuisvest in een sinds 1904 bestaand statig Herenhuis, welke in opdracht van professor Hugo de Vries is gebouwd en vervolgens bewoond. Deze professor was plantkundige en leraar aan de Hortus Botanicus in Amsterdam en heeft destijds veel betekend voor de ontwikkeling van het enten en kruisen van planten en bloemen

http://www.senotel.nl/hugodevries.html38

Carl Erich Correns (1864-1933) Im Botanischen Garten von Tübingen, wo

Leonhart Fuchs (1501-1566) im 16. Jahrhundert bereits einen Hortus Medicus aufgebaut hatte, begann Carl Correns 1894 seine Vererbungsexperimente, welche 1900 zur Wiederentdeckung der Mendelschen Vererbungsregeln beitrugen.

Correns erkannte durch seine Experimente aber auch, dass nicht alle Merkmale frei miteinander kombinierbar seien, sondern dass einige eindeutig untereinander gekoppelt sind (d.h. stets gemeinsam vererbt werden).

http://home.tiscalinet.ch/biografien/biografien/mendel.htm聯鎖遺傳 ?

39

Some references Correns, Carl. "G. Mendel's Regel über das Verhalten der

Nachkommenschaft der Rassenbastarde," Berichte der deutschen botanischen Gesellschaft 18 (1900), pp. 158-168. An English translation by Leonie Kellen Piternick, "G. Mendel's Law Concerning the Behavior of Progeny of Varietal Hybrids," appears in Genetics [1950], pp. 33-41, and Stern and Sherwood (1966), pp. 119-132.

Genetics. The Birth of Genetics: Mendel, de Vries, Correns

and Tschermak in English Translation. Supplement to Genetics 35, September 1950, No. 5 pt. 2.

http://www.modares.ac.ir/elearning/mnaderi/Genetic%20Engineering%20course%20II/Pages/history_of_genetics3.htm

40

我曾經在 Tübingen

Correns 待過的植物園Correns C 用的材料 Matthiola incana 紫羅蘭

41

Correns {'Bot. Cblt.,' 1900, 43, p. 97} has appeared describing his experiments with a glabrous [without hairs] and a hoary form of garden stock (Matthiola incana), and giving results as to these varieties, tested by self-fertilization, and also by recrossing the cross-breeds with them parental forms. The facts taken together are in fairly close agreement with the expectation given by Mendel's law, though the discrepancies are decidedly greater in this case than in the others.

Lastly, Professor Correns has also published {'Biblioth. Bot.,' 1901, Heft 53} an elaborate and important memoir on the results obtained in crossing varieties of maize.

http://post.queensu.ca/~forsdyke/bateson1.htm

42

Correns was a tutor at the University of Tübingen when he began to experiment with trait inheritance in plants in 1892. Correns already knew about some of Mendel's hawkweed plant experiments from Nägeli. Nägeli, however, never talked about Mendel's key pea plant results, so Correns was initially unaware of Mendel's laws of heredity.

However, by 1900, when Correns submitted his own results for publication, the paper was called: G. Mendel's Law Concerning the Behavior of the Progeny of Racial Hybrids.

Correns and de Vries were the ones who most clearly "redefined" Mendel's laws. Correns (with credit to de Vries) restated Mendel's results, giving us Mendel's law of segregation and Mendel's law of independent assortment. Karl Wilhelm von

Nägeli (1817-1891)

Eric von Tcshermak 的貢獻被忽略了 !

Nägeli 做這個也是八年

43

Erich von Tschermak-Seysenegg Because he was younger, and not as established

in the scientific community, Tschermak was worried about the acceptance of his paper given those of de Vries' and Correns'. However, he was able to rush his paper to press, and was accorded his share of attention as one of the rediscoverers of Mendel's laws.

Tschermak was a plant breeder, and his hybridization experiments were done with the idea of improving crops using the laws of heredity. He did most of the work himself, and produced high-yielding food crops such as wheat, barley, and oats. In 1903, Tschermak was appointed associate professor at the University of Agricultural Sciences in Vienna, and later became a full professor. He was a major influence in agriculture and plant breeding in Austria.

http://www.modares.ac.ir/elearning/mnaderi/Genetic%20Engineering%20course%20II/Pages/history_of_genetics3.htm

44

Tschermak worked with many varieties of peas, and though he obtained several results not wholly consistent with Mendel's law, and some actually conflicting evidence, the general tenour of his work is confirmatory. He gives, in particular, results as to the crossing of cross-breds with one or other of the pure forms.

Tschermak's numbers though insufficient for a thorough test, are in fair harmony with Mendel's hypothesis. He believes also that there is evidence that yellow is more decidedly dominant over green, than the rounded character is over the wrinkled, and on this point further experiments are required.

45

1866, Mendel published his lecture, a work that was to establish him as “the father of genetics”.

1869 Johann Friedrich Miescher (nuclein) 1873 Anton Schneider (meiosis) 1879 Walther Flemming (chromaton, mitosis) 1888 Wilhelm von Waldeyer-Hartz, (term

chromosome) 1902 Walter Stanborough Sutton. (chromosomes

carry the units of inheritance) 1904 Theodor Boveri (correlation between Mendel's

factors and chromosomes ) 1904 William Bateson (genetics) 1909 Wilhelm Johannasen (gene)

孟德爾以概念 ( 以 Elementet 稱呼他所追蹤的遺傳單位 ) 和假設的理論掌握自然的規律 ( 關係 ) 。但是概念必須有實物相對應，才能展現其存在的意義。

46

DNA to chromosome to DNA

1869 Johann Friedrich Miescher identifies a weakly acidic substance of unknown function in the nuclei of human white blood cells. This substance will later be called deoxyribonucleic acid, or DNA.

1924 Microscope studies using stains for DNA and protein show that both substances are present in chromosomes.

1928 Franklin Griffith, a British medical officer, discovers that genetic information can be transferred from heat-killed bacteria cells to live ones. This phenomenon, called transformation, provides the first evidence that the genetic material is a heat-stable chemical.

1944 Oswald Avery, Maclyn McCarty, and Colin MacLeod, identify Griffith's transforming agent as DNA.

http://www.csuchico.edu/anth/CASP/Carmosino_P.html

47

It was while working on pus cells at Tübingen in 1869 that Miescher made his fundamental discovery. It was thought that such cells were made largely of protein, but Miescher noted the presence of something that "cannot belong among any of the protein substances known hitherto."

He showed that the new substance was derived from the nucleus of the cell alone and consequently named it 'nuclein'.

Miescher was soon able to show that nuclein could be obtained from many other cells and was unusual in containing phosphorus in addition to the usual ingredients of organic molecules - carbon, oxygen, nitrogen, and hydrogen. It was not until 1871 that Miescher's paper, delayed by Hoppe-Seyler (who wanted to confirm the results), was published.

http://www.laskerfoundation.org/news/gnn/timeline/1869a.html

Miescher, Johann Friedrich II1844-1895 

Switzerlander

48

The discovery of chromosomes cannot be pinpointed to a single person. It was a consequence of the growing interest in the division processes of the fertilized egg.

Scientists on cell division : Anton Schneider, Eduard Strasburger, Otto Bütschli, Edouard van Beneden, Leopold Auerbach, Hermann Fol, Walther Flemming.

1873 and after

49

Walther Flemming 1843 - 1905

1879: he described and named "chromaton", "mitosis" and "spireme", made the first accurate counts of chromosome numbers and figured the longitudinal splitting of chromosomes.

http://www.nature.com/cgi-taf/DynaPage.taf?file=/nrm/journal/v2/n1/full/nrm0101_072a_r.html

50

Flemming observed for the first time that the chromosomes during cell division became split along their longitudinal axis, now known to consist of chromatids, and in 1880 he formulated the sentence: "Omnis nucleus e nucleo".

All nuclei come from nuclei

(1863), omnis cellula e cellula

51

He was the U.S. geneticist (and also surgeon) who provided the first conclusive evidence that chromosomes carry the units of inheritance and occur in distinct pairs.

The two papers (Sutton, 1902, 1903) written as a graduate student under E. B. Wilson at Columbia University formulated the concept that chromosomes carried the units of heredity and explained Mendel's laws.

1877-1916

Walter Stanborough Sutton.

http://www.kumc.edu/research/medicine/anatomy/sutton/surgical_career.htmlhttp://post.queensu.ca/~forsdyke/guyer.htm#Chromosomes%20in%20Heredity

52

While he was working as a graduate student at Columbia University, studying grasshopper cells, Sutton observed that chromosomes occurred in distinct pairs, and that during meiosis, the chromosome pairs split, and each chromosome goes to its own cell. Sutton announced this discovery in his 1902 paper On the Morphology of the Chromosome Group in Brachyotola.

I believe this creature is what Sutton has seen during his study at Columbia University (BC, 2004)

http://www.kumc.edu/research/medicine/anatomy/sutton/surgical_career.html

53

Theodor Boveri (1862-1915)

He saw that as egg cells matured, there comes a point where chromosome numbers are reduced in half. Boveri was one of the first to see evidence of the process of meiosis. (In the late 1880's and early 1890's)

When Mendel's laws were rediscovered in 1900, Boveri recognized the correlation between Mendel's factors and the cytology work being done on chromosomes (1904?).

Some one had already improved the staining technique for chromosomes

http://www.dnaftb.org/dnaftb/concept_8/con8bio.html

54

William Bateson (1861-1926)

William Bateson describes gene linkage, showing that more than one gene may be required for a particular characteristic or trait (1904).

A hereditary factor like, for example, the shape of the seed, the colour of the cotyledons or the colour of the seed shell shall be called a gene (following a suggestion of BATESON made in 1905).

http://post.queensu.ca/~forsdyke/bateson1.htm55

Wilhelm Johannasen (1857-1927)

Danish botanist Wilhelm Johannsen coined the word gene (1909) to describe the Mendelian units of heredity.

He also made the distinction between the outward appearance of an individual (phenotype) and its genetic traits (genotype).

The proposed word traced from the Greek word genos, meaning "birth". The word spawned others, like genome.

http://www.genome.gov/Pages/Education/Kit/main.cfm?pageid=24

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First page of a 1905 letter written by William Bateson, first Director of the John Innes Institute, to Adam Sedgewick, Cambridge professor. Bateson coined the term "genetics" in this letter. he felt the need for a new term to describe the study of heredity and inherited variations. But the term didn’t start spreading until Wilhelm Johannsen suggested that the Mendelian factors of inheritance be called genes.

http://www.dnaftb.org/dnaftb/concept_5/con5gallery.html

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