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Transcript of Epigenetics
More Methylation = Less gene expression DNA Methylation Think of the genome as the hardware, which is doing the work, and the epigenome as the software, which tells the genome how and when to do the work. The epigenome programs the genome. The following studies examine how early-life environmental exposures can impact the genome by systematically readjusting DNA methylation patterns. But how? Nature via Nurture All You Need is Love Increased pup licking and grooming (LG) and arched-back nursing (ABN) by rat mothers altered the offspring epigenome.
Compared to pups of high-nurturing mothers, pups of low-nurturing mothers carried the methyl mark on genes that normally inhibit stress responses.
This difference appeared within the first week of life and persisted into adulthood. You Are What Your Parents Ate… Feeding pregnant yellow mice methyl-rich diet (foods high in folic acid, vitamin B12, choline) silenced the effects of the agouti gene, and was not transmitted to offspring (who turned out to be thin and healthy).
These results suggest that maternal dietary supplementation may provide positive effects on the health of offspring. Maternal Exposure to Bisphenol A Conclusion Maternal Behavior Maternal Diet Just Say No to Toxins Dr. Moshe Szyf (McGill University):
The bottom line is that "[epigenetics] is all chemistry. What is most provocative here is the realization that the social environment can affect methylation patterns.”
Dr. Randy Jirtle (Duke University):
“When you have a mutation in a gene, you are stuck. You feel like you have a death sentence. There is no way of treating that…” but what epigenetics suggests is that you can actually “treat yourself simply by varying your diet or the way you live.” What the experts have to say: We now understand that our fate is not sealed by our DNA.
There are things we can do to change our genetics, and thus, change our health.
In fact, we are changing our genetics everyday by the air we breathe, the foods we eat, and even the thoughts we think. How does maternal lifestyle and behavior affect epigenetic modifications? By: Jyothi Manohar Both studies found that increased DNA methylation stopped the yellow “agouti” gene from being expressed. Of Mice and Methyl Maternal exposure to BPA altered patterns of gene expression by removing methylation at sites on the yellow “agouti” gene, thus expressing it.
This resulted in the birth of more yellow agouti offspring.
A methyl-rich maternal diet reversed DNA methylation effects of BPA exposure, resulting in more healthy brown offspring. High-LG-ABN rat mother Low-LG-ABN rat mother Interestingly, when they took the offspring of a low-LG-ABN mother and raised it with a high-LG-ABN mother (cross-fostering), the DNA methylation effects were reversed!
These results show that an epigenomic state of a gene can be established through behavioral programming, and it is potentially reversible. "Epigenetic programming by maternal behavior" (Weaver et al., 2004) "Where genes load the gun, the environment pulls the trigger." If we are the “caretakers” of our genetic road map, than each of us has far greater responsibility than we ever imagined! The next two studies examined the effects of DNA methylation on the expression of the yellow “agouti” gene in mice. Yellow agouti mice (Avy/a)
Prone to cancer and diabetes Brown mice (non-agouti-yellow)
Healthy "Maternal epigenetics and methyl supplements affect agouti gene expression in Avy/a mice." (Wolff et al., 1998) Environment-Induced Epigenetic Changes: What is Epigenetics? Epigenetics refers to any hereditary trait that is not determined by DNA sequences. Interestingly, these results suggest a possible association between increased plastics in current environments and rising obesity incidence, in humans. "Maternal nutrient supplementation counteracts bisphenol A-induced DNA hypomethylation in early development." (Dolinoy et al., 2007) 1) Amato, Ivan. "Genes Take a Back Seat." Chemical & Engineering News. N.p., 6 Apr. 2006. Web. <http://pubs.acs.org/cen/science/87/8714sci1.html>.
2) Dolinoy DC, et al. Maternal nutrient supplementation counteracts bisphenol A-induced DNA hypomethylation in early development. Proc Natl Acad Sci U S A. 2007 Aug 7;104(32): 13056-61. Epub 2007 Aug 1.
PubMed PMID: 17670942; PubMed Central PMCID: PMC1941790. <http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1941790/>
3) Price, Michael. "DNA Isn't the Whole Story." American Psychological Association. N.p., Oct. 2009. Web. <http://www.apa.org/monitor/2009/10/epigenetics.aspx>.
4) Samerotte, Kerry. "You Are What Your Mother Ate: The Science of Epigenetics." Harvard University, 6 Oct. 2010. Web. <https://sitn.hms.harvard.edu/sitnflash_wp/wp-content/uploads/2010/09/Epigenetics-Part-2.pdf>.
5) Weaver IC, et al. Epigenetic programming by maternal behavior. Nat Neurosci. 2004 Aug; 7 (8): 847-54. Epub 2004 Jun 27. PubMed PMID: 15220929. <http://www.ncbi.nlm.nih.gov/pubmed/15220929>
6) "Why Your DNA Isn’t Your Destiny." The Vreeland Clinic's Blog. N.p., 24 Jan. 2010. Web. <http://thevreelandclinic.wordpress.com/2010/01/24/why-your-dna-isn%E2%80%99t-your-destiny/>.
7) Wolff GL, et al., Maternal epigenetics and methyl supplements affect agouti gene expression in Avy/a mice. FASEB J. 1998 Aug;12(11):949-57. PubMed PMID: 9707167.
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