DNA magnified 850,000 times through a scanning electron
DNA day is coming up on Friday April 25th. This annual celebration of genetics and genomics was set up in 2003 to commemorate the sequencing of the human genome and the 50th anniversary of the solving of the structure of DNA.DNA day was thought of as an opportunity for teachers, students, and the general public to learn about DNA. And to have fun with it.

This should be a chance to pull DNA out of beef, strawberries, kumquats or even yourself and learn that you have around 100 billion miles* of DNA inside of you. In case you’re interested, that’ll reach from the Earth to Pluto and back when Pluto is farthest from Earth. And that is one person’s DNA.

Add up everyone’s DNA in the world and you get 125 million light years of DNA. (At least I think you do… these numbers are getting ridiculous!) That’ll get us to the galaxy Andromeda and back 25 times. Add up all the DNA on Earth and… OK, that’s probably enough of that.

There isn’t just a lot of the stuff but it is amazing to me how similar all human DNA is. The latest estimates are that people are around 99.5% the same at the DNA level. That means that all those light years of DNA are mostly the same old thing just copied over and over.

Notice the mostly. With 6 billion letters of code in every person, a 0.5% difference means 30 million differences between you and me. It is these differences that make me look different than you. And to a varying degree, make me act differently than you.

This code doesn’t work in a vacuum either. The environment can change how it works which is a big reason identical twins aren’t really identical. And one of the reasons why it is so hard to figure out the genetics of complicated diseases like diabetes or heart disease.

Our DNA also changes with time. Things in the environment might damage it. Or our own cells can make mistakes when they make copies of themselves. What this means is that today’s light years of human DNA will be different than the same stretched out DNA in 100 years.

This also means that you have some cells in your body have different DNA than the rest of your cells. And if a DNA change happens in sperm or egg cells, then they are passed on to the next generation. Which is where all the wonderful diversity around us originally came from.

As you can see, there is a lot about DNA to celebrate. It is huge and mysterious and we’re just starting to get a good grasp on what it is all about.

I plan to spend the morning of DNA day at The Tech Museum in San Jose exciting kids (and hopefully some adults) about DNA by running five different hands on genetics programs all at once. It’ll be a blast!

I have searched high and low for a list of DNA day activities here in the bay area but I haven’t come across any. Does anyone know about other DNA day celebrations here in the bay area?

* Each cell has 6 feet of DNA and we are made up of around 50-100 trillion cells.

Dr. Barry Starr is a Geneticist-in-Residence at The Tech Museum of Innovation in San Jose, CA.

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Hug-a-helix: celebrate DNA Day, April 25th 14 April,2008Dr. Barry Starr

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  • Ryan

    I love that you’re so excited about DNA, me too! It’s incredible. I’ve been learning epigenetics lately and it’s been blowing my mind! Also I’m listening to Betsey Dexter Dyer’s ‘Basics of Genetics’ TMS course and I just learned that 5/6 of our genome is viral, how cool is that! Anyway, thanks for your writeup, glad someone out there is as enthusiastic about DNA as I am!! lol

    • Barry

      It is great seeing someone else so excited. I love all that viral DNA too…it is a wonderful source for new genes.


Dr. Barry Starr

Dr. Barry Starr (@geneticsboy) is a Geneticist-in-Residence at The Tech Museum of Innovation in San Jose, CA and runs their Stanford at The Tech program. The program is part of an ongoing collaboration between the Stanford Department of Genetics and The Tech Museum of Innovation. Together these two partners created the Genetics: Technology with a Twist exhibition.

You can also see additional posts by Barry at KQED Science, and read his previous contributions to QUEST, a project dedicated to exploring the Science of Sustainability.

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