Jump to content

Soft inheritance: Difference between revisions

Add links
From Wikipedia, the free encyclopedia
Browse history interactively
← Previous editNext edit →
Content deleted Content added
VisualWikitext
Levalley (talk | contribs)
2,018 edits
No edit summary
Levalley (talk | contribs)
2,018 edits
No edit summary
Line 2: Line 2:
{{unreferenced}}
{{unreferenced}}


'''Soft inheritance''' is the term for a largely discredited set of theories. It was coined by [[Ernst Mayr]]{{citation}} to include such ideas as [[Lamarckism]],{{citation}} that an organism can pass on characteristics that it acquired during its lifetime to its offspring. It contrasts with modern ideas of [[Biological inheritance|inheritance]], which Mayr called [[hard inheritance]]. Since [[Gregor Mendel|Mendel]], modern genetics has held that the hereditary material is impervious to environmental influences (except, of course, mutagenic effects).<ref name="Richards">{{cite journal |author=Richards EJ |title=Inherited epigenetic variation—revisiting soft inheritance |journal=Nat. Rev. Genet. |volume=7 |issue=5 |pages=395–401 |year=2006 |month=May |pmid=16534512 |doi=10.1038/nrg1834 }}</ref> In soft inheritance "the genetic basis of characters could be modified either by direct induction by the environment, or by use and disuse, or by an intrinsic failure of constancy, and that this modified genotype was then transmitted to the next generation."<ref>{{cite book |author=Mayr, Ernst |authorlink=Ernst W. Mayr |editor=Provine, William B.; Mayr, Ernst |title=The Evolutionary synthesis: perspectives on the unification of biology |publisher=Harvard University Press |location=Cambridge |year=1980 |pages=1–48 |isbn=0-674-27225-0 }}</ref> Concepts of soft inheritance are usually associated with the ideas of [[Lamarck]] and [[Étienne Geoffroy Saint-Hilaire|Geoffroy]]. The concept of [[hard inheritance]] holds sway today, as Mayr points out.
'''Soft inheritance''' is the term for a largely discredited set of theories. It was coined by [[Ernst Mayr]]{{citations missing}} to include such ideas as [[Lamarckism]],{{citation}} that an organism can pass on characteristics that it acquired during its lifetime to its offspring. It contrasts with modern ideas of [[Biological inheritance|inheritance]], which Mayr called [[hard inheritance]]. Since [[Gregor Mendel|Mendel]], modern genetics has held that the hereditary material is impervious to environmental influences (except, of course, mutagenic effects).<ref name="Richards">{{cite journal |author=Richards EJ |title=Inherited epigenetic variation—revisiting soft inheritance |journal=Nat. Rev. Genet. |volume=7 |issue=5 |pages=395–401 |year=2006 |month=May |pmid=16534512 |doi=10.1038/nrg1834 }}</ref> In soft inheritance "the genetic basis of characters could be modified either by direct induction by the environment, or by use and disuse, or by an intrinsic failure of constancy, and that this modified genotype was then transmitted to the next generation."<ref>{{cite book |author=Mayr, Ernst |authorlink=Ernst W. Mayr |editor=Provine, William B.; Mayr, Ernst |title=The Evolutionary synthesis: perspectives on the unification of biology |publisher=Harvard University Press |location=Cambridge |year=1980 |pages=1–48 |isbn=0-674-27225-0 }}</ref>{{cite check}} Concepts of soft inheritance are usually associated with the ideas of [[Lamarck]] and [[Étienne Geoffroy Saint-Hilaire|Geoffroy]]. The concept of [[hard inheritance]] holds sway today, as Mayr points out.


One of the first statements in favour of hard inheritance was made by the English surgeon [[William Lawrence (biologist)|William Lawrence]] in 1819. His ideas on heredity were many years ahead of their time, as this extract shows: "The offspring inherit only [their parents'] connate peculiarities and not any of the acquired qualities".<ref>{{cite book |author=Lawrence, William FRS. |title=Lectures on physiology, zoology and the natural history of man |publisher=J. Callow |location=London |year=1819 }} There were a number of unauthorized reprints of this work, pirated (in the sense that the author went unrecompensed) but seemingly unexpurgated. These editions also lacked the protection of copyright, and date from 1819 and 1848. Some of them were by quite respectable publishers</ref> This is as clear a rejection of soft inheritance as one can find. However, Lawrence qualified it by including the origin of birth defects owing to influences on the mother (an old folk superstition). So [[Ernst Mayr|Mayr]] places [[Wilhelm His, Sr.]] in 1874 as the first unqualified rejection of soft inheritance. <ref>{{cite book |author=His W. |authorlink=Wilhelm His, Sr. |title=Unsere Körperform und das physiologische Problem ihrer Enstehung |publisher=Vogel |location=Leipzig |year=1874 }}</ref><ref>{{cite book |author=Mayr, Ernst |authorlink=Ernst W. Mayr |title=The growth of biological thought: diversity, evolution, and inheritance |publisher=Belknap Press |location=Cambridge, Mass |year=1982 |page=695 |isbn=0-674-36445-7 }}</ref> [[August Weismann]], in 1883, gave a comprehensive denial of [[Lamarckism]] (soft inheritance) and with his distinction between germ and soma provided a general ideology of hard inheritance which survives to the present day.
One of the first statements in favour of hard inheritance was made by the English surgeon [[William Lawrence (biologist)|William Lawrence]] in 1819. His ideas on heredity were many years ahead of their time, as this extract shows: "The offspring inherit only [their parents'] connate peculiarities and not any of the acquired qualities".<ref>{{cite book |author=Lawrence, William FRS. |title=Lectures on physiology, zoology and the natural history of man |publisher=J. Callow |location=London |year=1819 }} There were a number of unauthorized reprints of this work, pirated (in the sense that the author went unrecompensed) but seemingly unexpurgated. These editions also lacked the protection of copyright, and date from 1819 and 1848. Some of them were by quite respectable publishers</ref> This is as clear a rejection of soft inheritance as one can find. However, Lawrence qualified it by including the origin of birth defects owing to influences on the mother (an old folk superstition). So [[Ernst Mayr|Mayr]] places [[Wilhelm His, Sr.]] in 1874 as the first unqualified rejection of soft inheritance. <ref>{{cite book |author=His W. |authorlink=Wilhelm His, Sr. |title=Unsere Körperform und das physiologische Problem ihrer Enstehung |publisher=Vogel |location=Leipzig |year=1874 }}</ref><ref>{{cite book |author=Mayr, Ernst |authorlink=Ernst W. Mayr |title=The growth of biological thought: diversity, evolution, and inheritance |publisher=Belknap Press |location=Cambridge, Mass |year=1982 |page=695 |isbn=0-674-36445-7 }}</ref> [[August Weismann]], in 1883, gave a comprehensive denial of [[Lamarckism]] (soft inheritance) and with his distinction between germ and soma provided a general ideology of hard inheritance which survives to the present day.

Revision as of 17:36, 14 January 2012

[[expert-verify}}

Soft inheritance is the term for a largely discredited set of theories. It was coined by Ernst Mayr

to include such ideas as Lamarckism, {{citation}}: Empty citation (help) that an organism can pass on characteristics that it acquired during its lifetime to its offspring. It contrasts with modern ideas of inheritance, which Mayr called hard inheritance. Since Mendel, modern genetics has held that the hereditary material is impervious to environmental influences (except, of course, mutagenic effects).[1] In soft inheritance "the genetic basis of characters could be modified either by direct induction by the environment, or by use and disuse, or by an intrinsic failure of constancy, and that this modified genotype was then transmitted to the next generation."[2]

Concepts of soft inheritance are usually associated with the ideas of Lamarck and Geoffroy. The concept of hard inheritance holds sway today, as Mayr points out.

One of the first statements in favour of hard inheritance was made by the English surgeon William Lawrence in 1819. His ideas on heredity were many years ahead of their time, as this extract shows: "The offspring inherit only [their parents'] connate peculiarities and not any of the acquired qualities".[3] This is as clear a rejection of soft inheritance as one can find. However, Lawrence qualified it by including the origin of birth defects owing to influences on the mother (an old folk superstition). So Mayr places Wilhelm His, Sr. in 1874 as the first unqualified rejection of soft inheritance. [4][5] August Weismann, in 1883, gave a comprehensive denial of Lamarckism (soft inheritance) and with his distinction between germ and soma provided a general ideology of hard inheritance which survives to the present day.

Recent work in plants and mammals on the role of the environment on epigenetic modifications of DNA have led to the argument that inherited epigenetic variation is a kind of soft inheritance.[1]

This, however, is not one of the ideas explored in any detail in Mayr. Epigenetics does not claim that newly acquired traits can be directly transmitted to offspring without the mechanism of genetics (which was Lamarck's claim[6], but instead highlights the notion that the environment can help set up the functioning of existing genes. The notion that such change in the functioning of existing genes can lead to actual changes in the structure of genes remains highly controversial. Whether the term "soft inheritance" emerges as a term to capture the phenomena under study in epigenetics remains to be seen. Currently, it is difficult to find reputable scientific sources that use the term "soft inheritance" to refer to the studies (particularly on plants) that show that future genetic structures (not necessarily mutations) can be affected by past environmental events, except in the usual sense given in Darwin's theory of Natural Selection. Epigenetics, rather than soft inheritance, seems to be favored at academic institutions.[7]

References

  1. ^ a b Richards EJ (2006). "Inherited epigenetic variation—revisiting soft inheritance". Nat. Rev. Genet. 7 (5): 395–401. doi:10.1038/nrg1834. PMID 16534512. {{cite journal}}: Unknown parameter |month= ignored (help)
  2. ^ Mayr, Ernst (1980). Provine, William B.; Mayr, Ernst (ed.). The Evolutionary synthesis: perspectives on the unification of biology. Cambridge: Harvard University Press. pp. 1–48. ISBN 0-674-27225-0.{{cite book}}: CS1 maint: multiple names: editors list (link)
  3. ^ Lawrence, William FRS. (1819). Lectures on physiology, zoology and the natural history of man. London: J. Callow. There were a number of unauthorized reprints of this work, pirated (in the sense that the author went unrecompensed) but seemingly unexpurgated. These editions also lacked the protection of copyright, and date from 1819 and 1848. Some of them were by quite respectable publishers
  4. ^ His W. (1874). Unsere Körperform und das physiologische Problem ihrer Enstehung. Leipzig: Vogel.
  5. ^ Mayr, Ernst (1982). The growth of biological thought: diversity, evolution, and inheritance. Cambridge, Mass: Belknap Press. p. 695. ISBN 0-674-36445-7.
  6. ^ Jurmain, Robert, Lynn Kilgore et al. Introduction to Physical Anthropology. Wadsworth 2011. Pp. 29-39.
  7. ^ http://learn.genetics.utah.edu/content/epigenetics/

Further reading

Retrieved from "https://en.wikipedia.org/w/index.php?title=Soft_inheritance&oldid=471351108"