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Origin of the terms embryo, gamete and zygote

Published online by Cambridge University Press:  18 July 2012

Gonzalo Herranz
Gonzalo Herranz*
Affiliation:
Department of Medical Humanities, School of Medicine, University of Navarre, Apartado 177, 31080 Pamplona, Spain.
*
All correspondence to: Gonzalo Herranz. Department of Medical Humanities, School of Medicine, University of Navarre, Apartado 177, 31080 Pamplona, Spain. Tel: +34 948 425 600 ext. 6354. Fax: 34 948 425 630. e-mail: [email protected]
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Extract

The scope of this article is to answer two questions: first, when were the terms embryo (E), gamete (G) and zygote (Z) coined, and second, who were the scientists who put them in circulation? In order to clarify and document the origin of these three words, a vast amount of biomedical literature, particularly from the late 19th and early 20th centuries, has been reviewed; an undertaking made possible by the free access to the massive repository of available scientific literature on the Internet. Furthermore, as a result of this analysis, I would like to raise some ethical aspects of scientific publication, in particular the obligation of scientists to personally assess the quality and source of data they take from the literature and use in their publications.

Type
Research Article
Information
Zygote , Volume 20 , Issue 4 , November 2012 , pp. 313 - 320
Copyright
Copyright © Cambridge University Press 2012

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References

Notes

1 For the plural forms (embryos, gametes and zygotes), the abbreviations Es, Gs and Zs will be used.

2 http://www.word-origins.com/definition/embryo.html

3 Simpson, J.A. & Weiner, E.S.C. eds. (1989). The Oxford English Dictionary, 2nd edn.Oxford: Clarendon PressGoogle Scholar.

4 Homer. The Odyssey. For the Greek text: Montgomery, M. (1882). Homer. Odyssey, Book IX. Dublin: Brown & Nolan. The term E appears three times, in the Book IX, verses 245, 309, and 342. Curiously, it is used improperly: it is evident that Homer is not speaking of the unborn in the womb, but of the newborn lamb. See: Crusius, G.C. (1841). Vollständiges Griechisch-Deutsches Wörterbuch über die Gedichte des Homeros und der Homeriden. Hannover. Hahnschen Hofbuchhandlung: p. 156.

5 For example, in the treatises On regimen, On generation, and On the nature of the child.

6 See: Needham, J. (1934). A History of Embryology. Cambridge: University Press: pp. 51–6Google Scholar.

7 Parr, B. (1819). The London Medical Dictionary. Vol. I. Philadelphia: Mitchell, Ames, and White: p. 599Google Scholar.

8 The author of De Proprietatibus was not Bartholomaeus de Glanvilla, but Bartholomaeus Anglicus, who composed this outstanding encyclopaedic book around 1240.

9 (Pseudo) Albertus Magnus. (1655). De Secretis Mulierum. Amstelodami: Iodoam Janssonium; pp. 11–22.

10 Biggers, J.D. (1990). Arbitrary partitions of prenatal life. Hum. Reprod. 5, 1–6CrossRefGoogle ScholarPubMed.

11 The Oxford English Dictionary (see note 3).

12 Vines, S.H. (1886). Reproduction of Plants. Encyclopaedia Britannica, 9th edn, vol. XX. New York: Ch. Scribner's Sons. 425Google Scholar, col. 1.

13 Vines, S.H. (1886). Lectures on the Physiology of Plants. Cambridge: University PressCrossRefGoogle Scholar.

14 Foster, F.P. (1892). An Illustrated Encyclopedic Medical Dictionary, vol. III. New York: Appleton and Co.Google Scholar In the entry G, it is stated: ‘One of two similar or dissimilar reproductive cells, which by their fusion produce a new organism.’ [B, 77, 291 (α, 24); McNab, W.R. Sci. Proc. Roy. Dublin Soc., July, 1885, p. 451].

15 http://www.myetymology.com/english/gamete.html

16 http://dictionary.reference.com/browse/gamete

17 http://www.merriam-webster.com/dictionary/gamete

18 Skinner, H.A. (1976). The Origin of Medical Terms. 2nd edn, reprinted. New York: Hafner Pub. Co.Google Scholar; and Haubrich, W.S. (2003). Medical Meanings: A Glossary of Words Origins. 2nd edn.Philadelphia: American College of PhysiciansGoogle Scholar.

19 In fact, Mendel published only two articles on biological (botanical) subjects: Mendel, G. (1865). Versuche über Pflanzenhybriden. Verhandl Naturf Verein Brünn, 4, 3–46Google Scholar; and Mendel, G. (1869). Ueber einige aus Künstliche Befruchtung gewonnene Hieraciumbastarde. Verhandl Naturf Verein Brünn, 8, 26–31Google Scholar. His other three scientific publications deal with meteorological observations. The full list of Mendel's scientific publications, all of them submissions to the Brünn Naturalists Association, appears in the introductory notes Erich Tschermak wrote for a reprinting of Mendel's biological work: Tschermak, E, ed. (1901). Versuche über Pflanzenhybriden. Zwei Abhandlungen (1865 und 1869) von Gregor Mendel. Leipzig: W. Engelmann, pp. 56–57Google Scholar. Mendel, who certainly contributed basic ideas for understanding the concept of what later would be called G and Z, uses the terms and Pollen-Zelle and Ei-Zelle. The terms ‘pollen cells’ and ‘egg cells’, but not G or Z, appear in the faithful translation into English of Mendel's work, made by his admirer William Bateson (Bateson, W. (1902). Mendel ‘s Principles of Heredity: A Defence. With a translation of Mendel's original papers on hybridisation. Cambridge: University PressGoogle Scholar. This book, significantly amended, was republished 7 years later, (Bateson, W. (1909). Mendel's Principles of Heredity. Cambridge: University PressCrossRefGoogle Scholar).

20 For example, Miller, F.P., Vandome, A.F. & McBrewster, J. eds. (2009). Gamete. Mauritius: Alphascript Publishing.Google Scholar, reads: ‘The name G was introduced by the Austrian biologist Gregor Mendel’. And in Romich, J.A. (2009). An Illustrated Guide to Veterinary Medical Terminology, 3rd edn.New York: Delmar, p. 243Google Scholar, it is stated ‘Johann Gregor Mendel was the first to apply the term G in biology to mean sex cells’.

21 http://heybryan.org/school/Biology/notes/02–27-07,%20Mendelian%20genetics.html

22 Reference in OED reads: ‘1891 Hartog in Nature on September 17. 484 PARAGAMY and ENDOKARYOGAMY: gametal or vegetative nuclei lying in a continuous mass of cytoplasm fuse to form a zygote nucleus.’

23 It is this: ‘KARIOGAMY: the union of cells (gametes), cytoplast to cytoplast and nucleus to nucleus, to form a 1-nucleate cell, the zygote.’ Anonymous. (1891). Biology at the British Association. Nature 44, 481–4CrossRefGoogle Scholar, at 484.

24 This reference says: ‘1887 tr. De Bary's Fungi 495, Gamete, sexual protoplasmic body. . .which in conjugation with another gamete of like or unlike outward form gives rise to a body termed zygote. Same as conjugation-cell.’ In this way, the OED itself moves the birth of the term zygote from 1891 to 1887, and the credit for the word from Hartog to de Bary. But such attribution to de Bary is again a mistake. Only once de Bary used in the original German edition of his book (Vergleichende Morphologie und Biologie der Pilze, Mycetozoen und Bacterien. Leipzig: Engelmann, 1884) the term G (p. 139); but never the word Z. The OED refers logically to the English translation by I.B. Balfour of de Bary's book (Comparative Morphology and Biology of the Fungi, Mycetozoa and Bacteria. Oxford: Clarendon Press, 1887). The quotation in the OED is not de Bary's; it was written by the translator. In effect, Balfour, to help his readers to understand the complex terminology employed by de Bary, added to the book an appendix entitled Explanation of Terms. In the entry for G he says that the conjugation of Gs ‘gives rise to a body termed Z’. Curiously, in the Explanation of Terms there is no entry for Z. In the German original, de Bary used consistently the equivalent term zygospore.

25 Hartog, M.H. (1891). Some Problems of Reproduction: A Comparative Study of Protoplasmic Gametogony and Senescence and Rejuvenescence. Quart. J. Microsc. Sci. 33, 1–79Google Scholar. Hartog offers the following definition of Z: ‘In my terminology I have used the word[. . .]Z to designate the cell produced by their union [of Gs]’. Curiously, the article's recommended reading list includes two books of Eduard Strasburger (‘Befruchtung und Zelltheilung,’ Strasbürger [sic], undated; and ‘Neuere Untersuchungen,’ Strasbürger [sic], 1884).

26 The reference in the OED says: ‘1880 Pascoe. Zool. Chem. [sic] (ed. 2) p. 297’. It corresponds to: Pascoe, F.P. (1880). Zoological Classification: a Book of Reference, 2nd edn.London: Van VoorstGoogle Scholar. The OED's reference to p. 297 directs to the Glossary, although the word zygosis appears in p. 5 of the text, where it is described as ‘one mode of reproduction[. . .]by conjugation’.

27 The concept of zygosis took on a special meaning in the early years of the 20th century. As an anticipation to the debates on sociology and psychology of gender held many decades later, some scientists considered the expressions fertilization and fecundation inappropriate both biologically and sociologically, because those terms were expression of an archaic concept of development, and conveyed the idea, culturally unacceptable, of a passive female G fecundated by an active male G. Therefore, they feel preferable the use of zygosis to denote the fusion of Gs to form the Z, because it described neutrally the phenomenon and was free of social implications. Besides zygosis (suggested by Lankester), other words were proposed then to replace fertilization or fecundation: syngamy and amphimixis recommended respectively by Hartog and Weismann. Each of those neologisms followed different fates. See: Poulton, E.B. (1908). Essays on Evolution 1889–1907. Oxford: Clarendon Press; pp. 60–61Google Scholar.

28 There is general agreement that the noun ‘genetics’ to designate the science of heredity and variation in living organisms was first used by William Bateson in a letter to Adam Sedgwick, dated 18 April 1905. The text of this letter appears in: Bateson, B. ed. (1928). William Bateson, Naturalist. His Essays & Addresses. Cambridge: Cambridge University Press, p. 93Google Scholar.

29 What Bateson did with these last two words was simply to adapt the then already current term Z to prefixes reflecting the new way of understanding Mendelian inheritance. See: Schwartz, J. (2008). In Pursuit of the Gene. From Darwin to DNA. Cambridge, Mass: Harvard University Press, p. 114CrossRefGoogle Scholar.

30 Bardoe, C. (2006). Gregor Mendel: The Friar Who Grew Peas. New York: Abrams BooksGoogle Scholar.

31 In one of them, which allegedly ‘ensures accurate factual information’, we read that ‘In 1905, the English geneticist William Bateson (1861–1926) coined the term ‘genetics’, along with other descriptive terms used in modern genetics, among which include ‘allele (a particular type of gene)’, zygote (fertilized egg), ‘homozygosity’[. . .]. The History of Genetics – Genetics at the Dawn of the Twentieth Century. http://www.libraryindex.com/pages/2216/History-Genetics-GENETICS-AT-DAWN-THETWENTIETH-CENTURY.html

32 In his biography of Gregory Bateson, Lipset notes that the Gregory's father, William, had coined the term ‘genetic’ and introduced the word ‘zygote’, ‘homozygous’ ‘heterozygous’ and ‘allelomorph,’ later shortened to ‘allele ‘(Lipset, D. (1980). Gregory Bateson. The Legacy of a Scientist. Englewood Cliffs, NJ: Prentice-Hall Inc.Google Scholar). Lipset himself, 25 years later, reiterated that William Bateson, who became ‘Mendel's vehement advocate in British biology’, introduced the new terminology it demanded. Genetics, for the new science as a whole, but also Z, homozygote, heterozygote and allelomorph, for the internal relationships between genes.’ Lipset, D. (2005). Author and Hero – Rereading Gregory Bateson: The Legacy of a Scientist. Anthropol. Quart. 78, 899–915CrossRefGoogle Scholar.

33 Henig, R.M. (2000). The Monk in the Garden: Lost and Found Genius of Gregor Mendel, the Father of Genetics. Boston: Houghton Mifflin Co.Google Scholar (The book appeared simultaneously in the United Kingdom with another title: Henig, R.M. (2000). A Monk and Two Peas: The Story of Gregor Mendel and the Discovery of Genetics. London: Weidenfeld & Nicolson.Google Scholar) After referring to Bateson's invention of the term ‘genetics’ says Henig (pp. 229–230): ‘Bateson had already introduced four new terms, which have now been resurrected: ‘zygote’ – from the Greek zugotos, meaning ‘yoked’ – to describe the fertilized egg, the organism formed by the yoking together of two gametes; ‘homozygote’ (from the Greek homos, meaning ‘the same’) and ‘heterozygote’ (from heteros, meaning ‘different’) to describe, respectively, purebreds and hybrids; and ‘allelomorph’ (a compound of allelen, meaning ‘of one another’, plus morphe, meaning ‘form’) to describe the different versions of a particular trait.’ Henig states in a note that her ‘information on terminology is taken from Carlson, Elof Axel (1966). The Gene: A Critical History. Philadelphia: W.B. Saunders.Google Scholar But Carlson did not attributed to Bateson the invention of the term Z. He only transcribed some parts of the First Report to the Royal Society by Bateson & Saunders (see next note 34).

34 Bateson, W. & Saunders, E.R. (1902). The Facts of Heredity in the Light of Mendel's Discovery. Report I, presented Tuesday, December 17, 1901. Reports to the Evolution Committee of the Royal Society. London: Harrison & Sons: pp. 125–160Google Scholar. 126. A verbatim transcript of the report can be found in http://www.esp.org/foundations/genetics/classical/holdings/b/wb-02b.pdf

35 Bateson, W. (1902). Mendel's Principles of Heredity: A Defence. With a Translation of Mendel's Original Papers on Hybridisation. Cambridge: University PressGoogle Scholar. In a footnote on p. 18, Bateson warns: ‘The term ‘G’ is now used as equivalent of ‘germ cells’, and the term ‘Z’ is used here for brevity to refer to the body resulting from fertilization.’

36 Bateson, W. (1909). Mendel's Principles of Heredity. Cambridge: University PressCrossRefGoogle Scholar.

37 Bateson, W. (1928). Gamete and Zygote. A Lay Discourse (The Henry Sidgwick Memorial Lecture, 1917). In: Bateson, B. (1928). William Bateson, Naturalist. His Essays & Addresses Together with a Short Account of His Life. Cambridge: Cambridge University Press, p. 201Google Scholar.

38 In 1909, Bateson gave the term Z a new meaning. He designed as Z both the embryonic and the adult developed, through somatic cell divisions, from the cell resulting from the fertilization process. See: Bateson, W. (1909). Mendel's Principles of Heredity. Cambridge: University Press; p. 16CrossRefGoogle Scholar.

39 Bateson is recognized as the creator of the term Z in the Biography: William Bateson (1861–1926) offered by the Cold Spring Harbor Laboratory's Dolan DNA Learning Center. http://www.dnalc.org/view/16206-Biography-5-William-Bateson-1861–1926-.html.

40 In an introductory note to the collection of writings by William Bateson archived in the Library Association, it is said that ‘[Bateson] left his indelible mark in coining a lot of terminology related to modern Mendelian genetics, from allele to zygote, including the same term ‘genetics’.’ American Philosophical Society. William Bateson Collection 1902–1921. http://www.amphilsoc.org/mole/view?docId=ead/Mss.B.B319-ead.xml; query =; brand = default

41 For a short and informative biography of Strasburger, see: Finke, H.M. Eduard Strasburger – eine biographische Skizze. In Finke, H.M. & Moltmann, U.G. (1994). Hundert Jahre Strasburgers Lehrbuch der Botanik für Hochschulen. Stuttgart: G. Fischer, pp. 29–53Google Scholar. More accessible are, for example, Schwarz-Weig, E. Life and Work of Eduard Strasburger (1844–1912). http://www.deutsche-botanische-gesellschaft.de/html/047StrasburgerCV.html; and, in German Karsten, G. (1912). Nachrufe: Eduard Strasburger. Ber. Dtsch. Bot. Ges. 30, 61–86Google Scholar, The virtual version can be reached at: http://www.archive.org/stream/berichtederdeuts30deut #page/n781/mode/2up

42 deBary, A. Bary, A. & Strasburger, E. (1877). Acetabularia mediterranea. Bot. Zeit. 35, col 713–28Google Scholar, 729–43, and 745–58. The quoted passage appears in column 756. In fact, as shown below, the correct reference ought to be: Strasburger, E. (1877). Acetabularia mediterranea. Bot. Zeit. 35, 745–58Google Scholar, col 756. The publication date is 23 November 1877. The German original reads so: ‘Zum Schluss erlaube ich mir aber, da nun ihr ganzes Verhalten für Acetabularia klar vorliegt, für diese Schwärmer den namen Gameten vorzuschalagen[. . .]. Das Produkt der Paarung der Gameten könnte aber den Namen Zygote führen.’

43 deBary, A. Bary, A. (1877). Acetabularia mediterranea. Bot. Zeit. 35, col 713–28Google Scholar, 729–35, en col 735.

44 Strasburger, E. (1877). Über Befruchtung und Zelltheilung. Jenaische Zeitschr Naturwiss 11, 435–536Google Scholar.

45 Strasburger, E. (1878). Über Befruchtung und Zelltheilung. Jena: Verlag von Hermann Dabis.

46 See note 16, above.

47 In the interest of the terminology introduced, specifically, of the terms of G and Z, the article by de Bary & Strasburger is referred to in: Anonymous. (1878). Notes and Memoranda: Spore Nomenclature. J. Roy. Micros. Soc. 1, 372Google Scholar. But, surprisingly, it is not a direct reference, but only a citation through a secondary source (the Bulletin of the Botanical Society of France).

48 Anonymous. (1878). Science Notes. Botany: Acetabularia mediterranea. The Academy, A Weekly Review of Literature, Science, and Art 13, 79Google Scholar. This note has interesting information: according to it, the contribution of de Bary to the combined article on Acetabularia remained unpublished for 5 years. It mentions that Strasburger calls G to a swarm spore; and Z to the product of fusion of Gs.

49 For example, Fol, H. (1879). Recherches sur la Fécondation et le Commencement de l'Hénogénie chez Divers Animaux. Geneva: Henri Georg, pp. 294–5Google Scholar. Fol, citing the 1877 article in the Jenaische Zeitung, recognized Strasburger as the creator of the terms Z and G.

50 Vines, in his Encyclopaedia Britannica (1886) article, included among its bibliography, a reference to Strasburger's 1878 book Befruchtung und Zelltheilung, and took from it the term G, but he rejected the term Z, and used zygospore instead. Vines, S.H. Reproduction. Encyclopedia Britannica, 9th edn, Vol. XX: p. 425, col 1.

51 Bennet, A.W. & Murray., G. (1880). A reformed system of terminology of reproductive organs of the Cryptogamia. Quart. J. Micr. Soc. 20, 413–20Google Scholar. The authors reject Strasburger's simple new terms and forward instead a cumbersome system. On p. 418, they propose the use of zygosperm to replace Strasburger's Z, and words such as zoozygospheres as substitutes for Gs.

52 Sachs, J. (1882). Vorlesungen über Pflanzen-Physiologie. Leipzig: Vg. Von Wilhelm EngelmannGoogle Scholar. The English translation appeared 5 years later: Sachs, J. (1887). Lectures on the Physiology of Plants. Translated by Ward, H.M.. Oxford: Clarendon PressCrossRefGoogle Scholar.

53 For example, the famous Wilhelm Waldeyer, in a review on the state of knowledge on the sex cells, felt it necessary to clarify the meaning of the Termini technici applied to the reproductive processes in plants and, consequently, to simplify the terminology. He gave preference to G and Z, while acknowledging the usefulness of some terms as macrogamete, microgamete or zygospore. See: Waldeyer, W. Die Geschlechtzellen. In: Hertwig, O., ed. Handbuch der vergleichende und experimentelle Entwickelungslehre der Wirbeltiere. 1. Bd, 1.Teil. Jena: Verlag von Gustav Fischer, 1901–1903 (pp. 388–9)Google Scholar.

54 The book had three editions: Strasburger, E. (1875). Zellbildung und Zelltheilung. Jena: Hermann DabisGoogle Scholar; Strasburger, E. (1876). Zellbildung und Zelltheilung. 2e. Vermehrte und verbesserte Auflage, nebst Untersuchungen über Befruchtung. Jena: Hermann DabisGoogle Scholar; and Strasburger, E. (1880). Zellbildung und Zelltheilung. 3e. Völlig umgearbeitete Auflage. Jena: Verlag von Gustav FischerGoogle Scholar. The 2nd and 3rd editions include as a novelty the study of fertilization.

55 Strasburger, E. (1879). Neue Beobachtungen über Zellbildung und Zelltheilung. Bot. Ztg. 37, col 265–79Google Scholar, 281–8. (Col. 274).

56 Strasburger, E. (1884).Neue Untersuchungen über den Befruchtungsvorgang bei den Phanerogamen als Grundlage für eine Theorie der Zeugung. Jena: Verlag von Gustav FischerCrossRefGoogle Scholar.

57 G and Z are not used in the first of the issues (Strasburger, E. (1988). Histologische Beiträge. 1. Heft. Ueber Kern- und Zelltheilung im Pflanzenreiche, nebst einem Anhang über Befruchtung. Jena: Verlag von Gustav FischerGoogle Scholar), despite the fact, as the title shows, a whole section is devoted to reproduction of plants. In the fourth issue (Strasburger, E. (1892). Histologische Beiträge. 4. Heft. Über das Verhalten des Pollens und die Befruchtungsvorgänge bei den Gymnospermen. – Schwärmsporen, Gameten, pflanzliche Spermatozoiden und das Wesen der Befruchtung. Jena: Gustav Fischer VerlagGoogle Scholar), G is used profusely, and, by contrast, Z only occasionally.

58 Z is quoted once in the first edition, the same as in its English translation: Strasburger, E., Noll, F., Schenck, H. & Schimper, A.F.W. (1894). Lehrbuch der Botanik für Hochschulen. Jena: Verlag von Gustav FischerGoogle Scholar; Strasburger, E., Noll, F., Schenck, H. & Schimper, A.F.W. (1994). A Text-Book of Botany. London: Macmillan & Co.Google Scholar On the history of this book, see: Finke, H.M. & Moltmann, U.G. (1994). Hundert Jahre Strasburgers Lehrbuch der Botanik für Hochschulen. Stuttgart: G. FischerGoogle Scholar.

59 Nearly 30 years after coining the name G, Strasburger notes that ‘the sex cell of single chromosomes receives in plants the name gametophyte, in connection with the general designation of G which I recommended in 1877’[. . .]. Strasburger, E. (1905). Die stofflichen Grundlagen der Vererbung im organischen Reich. Versuch einer gemeinverständlichen Darstellung. Jena: Verlag von Gustav FischerGoogle Scholar; p. 13.