Epigenome & why stress can genetically affect ur g-kids

[BingoTheClowno]

http://www.wired.com/medtech/health/news/2005/08/68468
The more we learn about the human genome, the less DNA looks like destiny.
As scientists discover more about the "epigenome," a layer of biochemical reactions that turns genes on and off, they're finding that it plays a big part in health and heredity.

The epigenome can change according to an individual's environment, and is passed from generation to generation. It's part of the reason why "identical" twins can be so different, and it's also why not only the children but the grandchildren of women who suffered malnutrition during pregnancy are likely to weigh less at birth.
"Now we're even talking about how to see if socioeconomic status has an impact on the epigenome," Szyf said.
Researchers have already linked some human cancers with epigenetic changes. In a few years, scientists hope that doctors, by looking at an individual's epigenome, will be able to detect cancer early and determine what treatments to use.

http://www.epigenome.org/

http://www.pbs.org/wgbh/nova/genes/issa.html
It turns out that there are two kinds of modifications that can affect DNA. One is a biochemical modification that attaches straight to DNA itself, the most understood of which right now is DNA methylation. The other key event is the fact that DNA is wrapped around a series of proteins called histones. If these proteins hug the DNA very tightly, then it is hidden from view for the cell. A gene that is hidden cannot be utilized. It is the same as having a dead gene or a mutated gene. These are the kinds of things that can regulate gene expression and also become abnormal in cancer.

The best example of an epigenetic phenomenon is the face, says Dr. Jean-Pierre Issa (below). Skin, eyes, teeth, and hair all look different, but they contain exactly the same genetic information.


In the cell, DNA is wrapped around proteins called histones, shown here in green. When the histones squeeze the DNA tightly, they "hide" that section of genetic material from the cell.



Cigarette smoking can damage not only your genome but also your epigenome.


Epigenetic damage (seen here in more widespread darker areas) accumulates as we age. The DNA on the left is from an eight-year-old, while the corresponding stretch of DNA on the right is from a 60-year-old.


Skin that has been repeatedly exposed to the sun looks older than skin that hasn't because the skin's stem cells have had to divide more often to repair damage.


Our epigenome is affected by the environment around us, which includes even the food we eat.

[braincell]

The sun doesn't damage all skin the same way. People who have dark skin or tan quickly receive much less damage. The sun causes the body to make an enormous amount of vitamin D which prevents lung cancer and other types of cancer.

Previously we have been told to never be in the sun without sun blocking lotion. Now it is clear that 10 minutes a day in the sun without any protection is very beneficial. Sadly, once myths have been established, they are almost impossible to eliminate.

[BingoTheClowno]

The sun doesn't damage all skin the same way. People who have dark skin or tan quickly receive much less damage. The sun causes the body to make an enormous amount of vitamin D which prevents lung cancer and other types of cancer.

True.

Previously we have been told to never be in the sun without sun blocking lotion. Now it is clear that 10 minutes a day in the sun without any protection is very beneficial. Sadly, once myths have been established, they are almost impossible to eliminate.

I agree, moderate sun exposure helps human body with the absorption of vitamine D. However, we must not forget that the destruction of the ozone layer has stripped the atmosphere of an important UV protection layer. UV is know to be able to damage the DNA.
What I found to be amazing was how easy it is for any environmental changes to affect ones epigenome.

[braincell]

The sun causes the body to make vitamin D not to absorb it better and it is a gigantic quantity. Severe sunburn causes skin cancer not being in the sun.

http://discovermagazine.com/2008/jan/ye ... -your-life

[BingoTheClowno]

The sun causes the body to make vitamin D not to absorb it better and it is a gigantic quantity. Severe sunburn causes skin cancer not being in the sun.

http://discovermagazine.com/2008/jan/ye ... -your-life

I was not aware of that.

[at0m]

BingoTheClowno, recent research shows that DNA, apart from the protein sequence, contains a lot of 'spore' elements acting as switches on expressions of the sequence. They found boulemia and other related distortions in the genes of people who's ancesters went through famine.
In short, your DNA breaks down as you get older, and later children will carry these defects which would take many generations to iron out.
Smoking would not only cause cancer to the active smoker, but also increase chances for your offspring, even many years after the smoker quit - cos his DNA has been permanently damaged: the gene sequence remains, but switches on it are flipped over and are passed as such to the offspring.

Now I can understand this for male, as sperm is constantly produced, but females are born with all eggs already there...