Epigenetics 101

You’ve heard the word but what exactly does it mean.

Let’s break the word down.

Epi means on or above . Genetics is the study of heritable information passed on by a binary data system of genes encoded in DNA. Epigenetics is any heritable information that is created through any other means over what is in our DNA. It’s like a second layer of information on addition to the info contained within the DNA.

The end.

I hope that cleared everything up for you.

Ok. Time to get serious. Genetics is a field of biology that deals with traits that are passed down from one generation to the next. It became a rigorous area of study through the work of Gregor Mendel in 1866. There was a slow but steady progression into our knowledge of genetics until the next major breakthrough into the nature of genes. This came in the form of the discovery of the helical nature of DNA by a few scientists. Rosalind Franklin and Maurice WIlkins were able to take a picture of DNA using X-rays in the 1950’s while James Watson and Francis Crick were able to determine the 3-d structure of it thanks to the earlier work.

It was long thought that all of the heritable information of living organisms was contained within the genes of DNA. That turned out not to be the case. There were holes in that story and phenomena that could not be explained with this model.

Enter Epigentics

One such hole are the drastically different physical appearances of humans and our closest relatives the chimpanzee. We share over 99% of DNA with chimps and yet we look and behave so vastly different.

Because of natural variation within the human species it isn’t unreasonable to imagine a chimpanzee that is more closely related to us and share more DNA then another Human.

If all the information about who we are and what we look like, behave and so on is contained in the DNA then there should only be a 4% difference between everything a human is and looks like and everything a chimpanzee is and looks like.

Thank Odin that isn’t so.

While chimps can be cute I kinda like looking human.

The reason for this is epigentic in nature. Through certain mechanisms such as DNA methylation the same gene can be expressed differently in a different organism or different individual.

Epigenetic forces can turn genes on, turn them off, or determine how fully the genes are expressed.

Certain epigenetic elements can even be passed on for generations just as traditional traits.

Epigenetic changes stored in sperm and eggs are supposed to be erased in a process called reprogramming. The reprogramming process isn’t always complete however.

Conditioned fear responses in rodents were observed to be passed on to at least 3 generations.

They play almost as on important role as DNA and we are just beginning to explore this field.

There is a gene editing tool called CRISPR which can cheaply and effectively modify both the genome and epigenome. This is truly an exciting time to be alive. Hopefully not the “make a grave error that results in the extinction of our species type of exciting.


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