Let's Talk About Telomeres

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The aglets on the ends of shoelaces can be compared to telomeres on the ends of DNA. Jonas Bergsten/WIKIMEDIA

As I relish the last year of my 20s, I can’t help but see every sore muscle and creaky joint as a sign that I am on a swift slide toward immobility. This feeling is compounded by the fact that I recently threw out my back, got custom orthotics and started physical therapy. While bemoaning my descent into old age (with the overdramatic flare of a reality TV star), I began to wonder if there is a super-secret formula for aging gracefully.

We all know of a person, or two, who is still going strong well past 70 – someone with the spunk of Betty White and the energy of Patrick Stewart – right? I can’t help but wonder: what sets these super agers apart?

I recently had my DNA sequenced through 23andMe. I sent my sample in before the FDA ordered the company to stop providing health information to customers. As a result, I got the full health rundown, from inherited conditions to traits to health risks.

One intriguing result was labeled, “Biological Aging.” 23andMe indicates whether certain markers on your DNA predispose you to cells that appear older, younger or average, as compared to the general population. According to 23andMe, these “results are based on preliminary research for six reported [DNA] markers,” citing a 2013 study published in the journal Nature.

Now, 23andMe admits that, “preliminary research includes results of studies that still need to be confirmed by the scientific community.” So, it’s important to take any conclusions with a grain of salt. But, according to my results, I have five markers that indicate “typical telomere length on average,” and one marker that indicates “shorter telomeres on average, equivalent to those of a person 2.99 years older.” 

DNA telomeres

So, what are telomeres? Telomeres are DNA-protein structures found at both ends of each chromosome. When a cell prepares to divide, it organizes all of its DNA into a coiled bundle called a chromosome. Without the telomeres, the individual chromosomes might stick together or fall apart. Additionally, the telomeres protect the genetic information at the end of the DNA strand, ensuring that none of the sequence is lost during DNA replication.

If you think of a strand of DNA as a shoelace, then the aglets on each end (the plastic pieces that keep the shoelace from fraying) are the telomeres. Though these plastic pieces may wear away over time, the shoelace in between generally stays intact. In a similar way, telomeres degrade with each replication, but ensure that the genetic information they bookend remains preserved.

Eventually the telomeres become too short for the cell to divide any more. Without cell replication, tissues can no longer easily repair themselves. “Telomere length may therefore serve as a biological clock to determine the lifespan of a cell and an organism,” according to a study from 2011.

A geneticist by the name of Richard Cawthon was the first scientist to make the link between telomere length and aging. Cawthon, and his colleagues at the University of Utah, studied 143 subjects over the age of 60, according to a study published in 2003. Those with shorter telomeres in their blood DNA had a poorer survival rate.

Now, there’s no way of knowing if White and Stewart are the lucky owners of long telomeres. And, just because you have longer telomeres, doesn’t mean you’re guaranteed many years to come. So many other factors are at play, such as diet, exercise, smoking habits and stress. In fact, stress can lead to shorter telomeres, one study suggests.

So, I won’t rest my laurels on my (mostly) average telomeres quite yet. Now, if you’ll excuse me, I’m off to physical therapy to fix this bum knee…and then maybe some meditation for good measure.

Check out the University of Utah's Genetic Learning Center to learn more!

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