Methylation Madness

Hey, so for those people that aren’t really into physics, I thought I’d test the waters with a biology post. The other one was pretty dense, from the feedback I’ve been getting. I’ll be sure to break it down better next time. This post should be a pretty easy read.

his is what most people get used to when they think of genetics. Dominant genes, recessive genes.

There are also codominant genes: an example is blood type. Have you ever heard “My blood type is AB”? A is one gene, and B is another gene. However, one is not dominant over another, so you just say it together: AB.

There’s also something called incomplete dominance. That is where a gene is partially dominant over another, and the phenotypic result is sort of a mix. For example, a red flower mixed with a white flower might make a pink flower if one color is not completely dominant over another.

Phenotype is something that can be noticed without going into the DNA and looking at the genes.

So if in the punnet square above, T was for “big eyes” and t was for “small eyes”, the eye size would be the phenotypic results, and the letters Tt would be the genotypic results. According to the punnet square, genes are always predeterimed by your ancestry.

But that brings me to DNA methylation.

What if emotions were inherited?

That’s what can happen, according to the theory of epigenetics.

Emotions are accompanied with chemical releases. For example, if a person is stressed out, they experienced a flow of cortisol, GH, and other stress hormones. At certain periods in their life, these epigenetic effects can be transferred on to their kids.

Take 9/11. Women pregnant during the September 11 attacks were stressed out, and in turn had kids who were more prone to experience high stress levels. Another example is the Holocaust. When a human’s body doesn’t get enough food, it tells itself that it is growing up in an environment of poverty, and it needs to slow down its metabolism (food processing ability), and hold on to every bit of food.

The children of concentration camp survivors grew up in regular environments- milk in the fridge, bread on the table. However, their gene for a regular metabolism had been suppressed.

These victims- Holocaust, and 9/11 survivors, were not BORN with genes for high stress and slow metabolism. Their bodies made these changes as they underwent starvation and stress.

DNA methylation can be explained by a simple process- it suppresses a gene by attaching a protein compound (a type of which is a methyl group) over a gene, so it can’t be “read” (transcripted) and put into effect.

Using the 9/11 example, if a gene says “not to be stressed out”, and it is suppressed, then the flow of stress hormones will increase.

The compound labeled “Histone 1” is a type of methyl group- in other words, a protein compound.
To see the picture, click here: http://en.wikipedia.org/wiki/File:DNA_methylation.jpg

The above diagram is an example of DNA methylation.

Most of the examples I’ve used so far are about females’ effect on the zygote (baby). However, male behavior can effect the epigenetics of a cell too.  When males undego anticancer therapy, this affects the epigenetics of a sperm cell.

To learn more about methylation, click here: http://en.wikipedia.org/wiki/DNA_methylation

-pia

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