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Three epigenetic information channels and their different roles in evolution.

Shea N, Pen I, Uller T - J. Evol. Biol. (2011)

Bottom Line: However, the evolutionary implications of such alternative mechanisms of inheritance remain unclear.Selection-based epigenetic information is more likely to conflict with somatic cell inheritance than is detection-based epigenetic information.Consequently, the evolutionary implications of epigenetic mechanisms are different for unicellular and multicellular organisms, which underscores the conceptual and empirical importance of distinguishing between these two different forms of transgenerational epigenetic effect.

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Affiliation: Faculty of Philosophy and Somerville College, University of Oxford, Oxford, UK.

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Somatic cell inheritance takes place between cells in the lifetime of an organism. Detection-based effects are based on epigenetic factors which are sensitive to the parent's environment and are transmitted from parent to offspring. Selection-based effects are generated by selection over and are transmitted down many generations of organisms, subsuming the timescale of both detection-based effects and somatic cell inheritance.
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fig02: Somatic cell inheritance takes place between cells in the lifetime of an organism. Detection-based effects are based on epigenetic factors which are sensitive to the parent's environment and are transmitted from parent to offspring. Selection-based effects are generated by selection over and are transmitted down many generations of organisms, subsuming the timescale of both detection-based effects and somatic cell inheritance.

Mentions: The potential conflict arises if resetting does not occur piecemeal. If all epigenetic marks of a particular sort – all methylation marks, say – are reset during somatic embryogenesis, then there is no prospect of any of those marks forming the basis of selection-based effects. Global resetting would have the effect of treating methylation marks as a dedicated channel for somatic cell inheritance, blocking its use for selection-based effects. From one point of view, this observation is rather pedestrian: of course epigenetic marks cannot be the basis of long-run selection if they are reset in each generation. It is more interesting from the evolutionary point of view because it emphasizes a trade-off between the benefits of multicellularity using a given epigenetic mechanism for cell differentiation and heredity, and the benefits of using those same mechanisms as a channel for selection-based effects. This evolutionary trade-off represents a conflict between information channels (see Fig. 2).


Three epigenetic information channels and their different roles in evolution.

Shea N, Pen I, Uller T - J. Evol. Biol. (2011)

Somatic cell inheritance takes place between cells in the lifetime of an organism. Detection-based effects are based on epigenetic factors which are sensitive to the parent's environment and are transmitted from parent to offspring. Selection-based effects are generated by selection over and are transmitted down many generations of organisms, subsuming the timescale of both detection-based effects and somatic cell inheritance.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3116147&req=5

fig02: Somatic cell inheritance takes place between cells in the lifetime of an organism. Detection-based effects are based on epigenetic factors which are sensitive to the parent's environment and are transmitted from parent to offspring. Selection-based effects are generated by selection over and are transmitted down many generations of organisms, subsuming the timescale of both detection-based effects and somatic cell inheritance.
Mentions: The potential conflict arises if resetting does not occur piecemeal. If all epigenetic marks of a particular sort – all methylation marks, say – are reset during somatic embryogenesis, then there is no prospect of any of those marks forming the basis of selection-based effects. Global resetting would have the effect of treating methylation marks as a dedicated channel for somatic cell inheritance, blocking its use for selection-based effects. From one point of view, this observation is rather pedestrian: of course epigenetic marks cannot be the basis of long-run selection if they are reset in each generation. It is more interesting from the evolutionary point of view because it emphasizes a trade-off between the benefits of multicellularity using a given epigenetic mechanism for cell differentiation and heredity, and the benefits of using those same mechanisms as a channel for selection-based effects. This evolutionary trade-off represents a conflict between information channels (see Fig. 2).

Bottom Line: However, the evolutionary implications of such alternative mechanisms of inheritance remain unclear.Selection-based epigenetic information is more likely to conflict with somatic cell inheritance than is detection-based epigenetic information.Consequently, the evolutionary implications of epigenetic mechanisms are different for unicellular and multicellular organisms, which underscores the conceptual and empirical importance of distinguishing between these two different forms of transgenerational epigenetic effect.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Philosophy and Somerville College, University of Oxford, Oxford, UK.

Show MeSH
Related in: MedlinePlus