Pre-Survey in Partners  True or False survey

Epi-what? Epigenetics?  Epi = outside, so “Outside our genes”  We have known DNA can control how we grow, develop, how long we live…  But by observing the lives of identical twins, scientists have noticed that as these twins got older, the differences in their appearance, lives and health added up- but Why?  Epigenetics!

PBS: TWINS Video (14 min)  igenetics.html igenetics.html

 We used to think that a new embryo's epigenome was completely erased and rebuilt from scratch. But this isn't completely true. Some epigenetic tags remain in place as genetic information passes from generation to generation, a process called epigenetic inheritance.  Epigenetic inheritance is an unconventional finding. It goes against the idea that inheritance happens only through the DNA code that passes from parent to offspring. It means that a parent's experiences, in the form of epigenetic tags, can be passed down to future generations.  As unconventional as it may be, there is little doubt that epigenetic inheritance is real. In fact, it explains some strange patterns of inheritance geneticists have been puzzling over for decades.

Notes #3: Epigenetics Wait, there’s more to DNA? This is the last new topic on your test next ______________!

Vocabulary  Genes are the instruction manual for the development and maintenance of the body.  The epigenome is a second set of instructions interacting with DNA that activates or suppresses the expression of particular genes.  Expression: Whether or not each gene is read or not read by a cell.  Ex: A heart cell does not express the DNA genes for being a brain or skin cell but it does express the DNA genes for how to be a heart cell.  Epigenetics is the study of the changes in gene activity that does not involve actual changes to the DNA code.

How does Epigenetics work?  The environment you live in and the experiences you have (like starvation, smoking, etc.) can cause changes how your DNA is read by proteins- gene “expression”.  This in turn changes how your body functions.  These changes in gene expression can be passed on to your children…  So the experiences you have can affect not only affect your health but the health of your children and their children…

5 Known Influences on the animal Epigenome: 1. Diet & Nutrition 2. Physical Activity 3. Stress 4. Toxins & Air Quality 5. Sleep

1. Diet  The nutrients the body extracts from food (in which organ? ) are changed into molecules the body needs and can use. Methyl groups are important genetic tags that silence genes and they are one of the molecules made from a healthy diet.  For adults, a methyl-deficient diet leads to a decrease in DNA methylation, but the changes are reversible when methyl is added back into their diet.

Dietary Sources of Methylates & Acetylates  Nuts & Seeds  Peppers  Broccoli  Garlic  Milk  Whole Grain  Soy  Fish  Beef & Veal  Chicken  Liver  Egg Yolks (not egg whites!)

Case Study: Famine

2. Physical Activity  There is evidence that hormones produced during physical activity may change your epigenetics  Not exercising increases the risk of depression & heart disease

3. Stress  Chemicals released in the body during times of stress interact with the epigenome.  Many studies are focusing on the effect of the stress hormone cortisol, and how it influences epigenetic tags.  Too much regular stress increases the risk of obesity, malnutrition, hair loss, and more.

4. Toxins  These are potentially harmful substances to gene expression that include alcohol, tobacco, and exposure to pesticides, air pollutants, and harmful metals such as lead and nickel.  Smoking increases the risk of developing asthma and a shortened lifespan. (and those around it- 2 nd hand smoke  )  Living in a big city with poor air-quality can increase the risk of developing lung cancer.

Mother BPA & Baby’s Obesity  Bisphenol A (BPA) is a compound used to make some plastics. It is in many consumer products, including water bottles and tin cans.  Controversial reports questioning the safety of BPA came out in 2008, prompting some manufacturers to stop using the chemical.  In the laboratory, BPA appears to reduce methylation of the agouti gene causing gene overexpression:  In the strain of mice that was studied, yellow mothers give birth to pups with a range of coat colors from yellow to brown.  When mothers were fed BPA, their babies were more likely to be yellow and obese—like the one shown on the left.

5. Sleep  Not getting enough sleep not only decreases mental function and coordination the next day, but continual lack of sleep changes your natural Circadian Rhythm, which controls your daily function by sensing light & releasing hormones to help you wake up and to go to sleep.  Lack of sleep increases your stress-hormone release, increasing your blood pressure and slowing digestion. This negatively affects your health over long periods of time.  This is observed especially in people who work the night- shift, sleeping during the day and waking up at night.  The light TVs, cell phones & computers give off confuses this rhythm, and can make it hard to fall asleep, especially if watching in a dark room close to bedtime.

Pregnancy  A mother's diet, stress, smoking, air quality, sleep, and exercise during pregnancy and your diet as an infant can affect your epigenome in ways that stick with you into adulthood.  Animal studies have shown that a diet with too little methyl-donating folate or choline before or just after birth causes certain regions of the genome to be under- methylated for life.  Many genes get over-expressed.

Starvation during Pregnancy  If a mother doesn’t get enough food or high nutrition during pregnancy, she creates epigenetic changes in the still- developing baby that put it at a higher risk of becoming obese later in life.  Ex. This is why its important expecting mothers take prenatal vitamins to make sure they get all the vitamins they need

Don’t Count Dad Out!  So if a pregnant mother's diet can affect the child's epigenetic outcome, can dad's diet do the same? Quite possibly, according to scientists who delved into the well-kept, historical records of annual harvests from a small Swedish community.  These records showed that food availability between the ages of nine and twelve for the paternal grandfather affected the lifespan of his grandchildren. But not in the way you might think…

Food Supply & Child Lifespan  Shortage of food for the grandfather was associated with extended lifespan of his grandchildren.  Food abundance, on the other hand, was associated with a greatly shortened lifespan of the grandchildren. Early death was the result of either diabetes or heart disease.diabetesheart disease  Could it be that during this critical period of development for the grandfather, epigenetic mechanisms are "capturing" nutritional information about the environment to pass on to the next generation?