DNA getting smaller everytime it replicates?

[Nano]

DNA getting smaller everytime it replicates??

Today in biology class, my teacher said that DNA gets smaller everytime it replicates. He also said that this is the main cause of aging (he said that the "shortening" of DNA ending up chopping off important genes later in life, which led to an increased probability of diseases like cancer as we age because our cells have divided so many times)

Well, I tried to look this up, but I cannot find any information or research about DNA getting smaller after replication. Any idea what he was talking about? If it is true could you point me towards some online reading on the subject?

 

[Monique]

It's the telomere problem, researchers were awarded the Nobel prize this year for discovering the mechanism: http://nobelprize.org/nobel_prizes/medicine/laureates/2009/press.html

 

[Nano]

thanks, that was really helpful!

 

[Monique]

You're welcome

 

[AyazM]

Telomeres are repetitive sequences at the ends of the arms of a chromosome. The enzyme telomerase is responsible to replicating these sequences. Telomerase usually functions in stem cells and cancer cells and is one of the major mechanisms of the survival of cancer cells. Aging is a consequence of those repetitive sequences not being replicated and therefore losing information gradually.