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Epigenetics
- Heritable traits that do not involve changes to the underlying DNA sequence
- Epigenetic can also describe any aspect other than DNA sequence that influences development
- Epidgenetic factors can cause genes to behave (or "express themselves") differently
- Modifications of the activation of certain genes, but not the basic DNA structure
- Additionally, the chromatin proteins associated with DNA may be activated or silenced
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Epigenetic changes are preserved when cells divide
- Most changes only occur within the course of one individual's lifetime
- -If change takes place in somatic cells
- -But, if an epidgenetic change has been caused in a sperm or egg cell that results in fertilization...
- THESE CHANGES ARE INHERITED
sounds like someone we met earlier....Lamarck
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Mechanism of Epigenetic Influence over gene expression
- Chromatin Remodeling
- --If the way that DNA is wrapped around the histones changes, gene expression can change too
- 2 Ways
- --Changes to histone (protein portion)
- --Or DNA can have methyl (CH3) groups added to it
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Epigenetic influence over gene expression
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Epigenetic changes in response to environmental exposure
- EXAMPLE: mice given dietary supplements show epigenetic changes
- --Affecting fur color, weight, and risk of developing cancer
- --changes reflected in offspring of mice receiving supplement
- ---due to more methylation
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