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  1. 1. EpigeneticsBy: Erin WerkingBlock 2Honors Biology
  2. 2. What Is Epigenetics? All the genetic modifications excluding changes in the actual DNA sequence. Modifications include adding molecules, like methyl groups, to the DNA. This changes the appearance and structure of DNA which alters how that gene can interact with the transcribing molecules in the cell’s nucleus.
  3. 3. What is EpigeneticInheritance? The fact that non-genetic variations that are obtained during an organism’s life can be possibly be passed on to that organism’s offspring. An example of this would be that brain and skin cells have exactly the same DNA, but different functions and forms. So, there must be something that makes skin cells stay skin cells and brain cells stay brain cells when they divide.
  4. 4. How Does It Work? Epigenetic modifications turn genes on or off which prevents or allows the gene to make a protein. One type of modification is DNA Methylation. The addition of methyl groups to the backbone of the DNA can help distinguish the gene copy inherited from the mom or the one from the dad.
  5. 5. Experiments With Epigenetics When fruit flies are exposed to certain chemicals they get rough growths on their eyes and at least 13 generations after them are born with it too (and generations 2-13 weren’t exposed to the drug). A pregnant rat was exposed to a chemical that can alter reproductive hormones. It had generations of sick offspring. People who aren’t well-fed as a child are known to have children and grandchildren with higher risks for diabetes and cardiovascular disease.
  6. 6. Experiments with Epigenetics Smoking and over-eating can make the genes for obesity over-express themselves and the genes for longevity under-express themselves. Men who smoke before puberty tend to have sons who can’t produce sperm, have higher body mass indexes and shorter life expectancies.
  7. 7. Experiments with Epigenetics The rise in peanut allergies may be because of baby lotions containing peanut oil. Pregnant women with high maternal anxiety are known to have children with asthma. Little kids who are kept very clean are at higher risk for eczema.
  8. 8. Sweden Study In Norrbotten, Sweden in the 19th century there were very few people. If they had a bad harvest, people would starve. 1800, 1812, 1821, 1836, & 1856 the crops were horrible and people suffered. 1801, 1822, 1828, 1844 & 1863 the crops were bountiful and the people had feasts.
  9. 9. Sweden Study The study showed that pregnant women who ate poorly tended to have children with a higher risk for cardiovascular disease when they got older. Children that went from having a normal harvest to a feast the next year were known to have children and grandchildren with far shorter lives. When certain socioeconomic variations were controlled it came out to be that the future generations would die 32 years before their peers.
  10. 10. Epigenetic Changes But throughout all of those studies and experiments, the change was not in the DNA itself, but the new traits were passed on by epigenetic means. Epigenetic changes could possibly be permanent. The changes represent a response to an environmental stressor. The response can be inherited, but once the stressor is taken away, the marks will fade and the DNA code will go back to its original programming.
  11. 11. Contributions to Science Workand Society The new evidence for epigenetic inheritance has had great implications for the study of evolution. It extends the span of evolutionary thinking and is leading to ideas of heredity that include development. And it also suggests that acquired traits can be heritable, so Lamarck wasn’t completely wrong.
  12. 12. The Good News Scientists are learning to manipulate epigenetic marks and are making drugs that will treat sickness by turning off the bad genes and turning on the good ones.
  13. 13. Future Implications Scientists are hoping to develop epigenetic drugs to help people with diabetes, cancer, Alzheimer’s, schizophrenia, autism, etc. They are hoping that further research will help answer why one identical twin can suffer from asthma or bipolar disorder and the other one doesn’t. Or why autism is four times more likely in a boy than a girl.