Junk DNA?

Posted by Jack

Most of the time when people talk about “junk DNA” they mean DNA that doesn’t have a function. In other words, it’s DNA that does not have a specific purpose.

It turns out we were too quick to call this DNA junk.  We have discovered a lot of functions for DNA we didn’t know about before. In fact, it seems most “junk DNA” does have a purpose.

We know now that a lot of “junk DNA” is around to tell our bodies when, where and how much to turn on a gene. New research tells us that most of the rest of the junk probably does unknown but important things too.

When we talk about DNA we usually focus on genes. This is because genes are the part of DNA that carries the information to make proteins. Proteins are the chemical machines that do everything in your body from making the pigment in your skin, to causing your heart muscles to contract.

The interesting thing is not that much of your DNA actually carries the specific information for proteins. In other words, not a lot of your DNA is taken up with genes, or ‘coding regions.’ When the human genome was sequenced in 2001 scientists found that only about 3% of human DNA was genes and the rest was noncoding DNA.

This might make more sense if you think of your DNA like a cookbook with all the recipes you will ever eat. The genes are like the ingredients you need to make a recipe.

But most of the cookbook isn’t the list of ingredients; it’s the instructions of what to do with them. What temperature to use, when to add certain ingredients, and so on. This is the information found in all of that junk DNA.

http://genetics.thetech.org/ask-a-geneticist/junk-dna-not-so-junky