One Family, Different Clocks

  • Published5 Sep 2012
  • Reviewed5 Sep 2012
  • Source BrainFacts/SfN

The brain is the home of the body’s internal clock. Genetics can alter this clock, as Jaime Tartar and Tatiana Viena from Nova Southeastern University explain. Their video won second place in the 2012 Brain Awareness Video Contest and was voted the fan favorite in the People's Choice Contest.



Hi my name is Elysse and my sleep schedule is a bit different than those of my family members. Every day I wake up very early, in fact I wake up at 4 in the morning… sometimes at 3. Now, I am old enough not to bother my mom, my dad or my sister, I just read, play or wait until everyone else wakes up.                              

One day, I asked my mom why I was unlike everyone else in my family. She said that my clock was different than hers, my dad’s and my sister’s, but very similar to my grandpa’s. 

She also said: “it runs in the family”. I wondered what she meant by that and went on a quest to solve the mystery of “The family with different clocks”, and this is what I found…

Our bodies really have a clock! Not just a ticking clock, of course, but a biological clock!  This clock tells your body when it’s time to wake up and when it is time to go to sleep. Can you guess where this clock is located? Not on your wrist of course! (laughs) It is located in the most amazing part of your body: THE BRAIN!

What part of the brain you may ask? Our internal biological clock is located in the hypothalamus, in a special place called the suprachiasmatic nucleus. I know it is not an easy word, so let’s just call it: SCN. SCN is responsible for our day and night cycles which are also known as circadian rhythms. So my mom was right, I had a clock… but why was it different from everyone else’s? I went on with my search and I discovered something very interesting!!! 

The SCN cells contain genes that make proteins. These proteins help your body know when it’s time to wake up and when it is time to go to sleep.  If any of these “clock genes” are slightly different, in other words “mutated”, it would cause people to have different sleep and wake up times.  I was now getting down to the bottom of this situation!!!!

For example, a change in a gene called Per2, causes people to wake up very early and go to sleep very early.  For that reason, they are called “larks”. Yes, I know what you are thinking!!!! That sounds a lot like me!!! But what is more important, it “runs” in families… no wonder grandpa did the same thing!!

I did not stop there, I learned that another clock gene: Per3, would make people do the complete opposite I do, they go to bed really late and wake up really late.  For that reason, they are called “owls”.  This was so cool!!!

Finally, another gene, DEC2 would make people only sleep for a few hours without making them tired. Yes… my mom wished she had that one! (laughs)  Wow, this gene ‘thing’ is actually amazing!!!!! Well, as you can see my mom was right on the ball, my clock is different than everyone else, but my grandpa and it is very possible we have this special gene.  I am glad I solved this family mystery!  Thanks to neuroscience, I learned a lot along the way and I hope you did the same! 

Bye Everyone!!

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