It's a question we've all pondered at one time in our lives or another: when will I die?

Now, a research team at Brigham Young University has uncovered the answer to that elusive question, which lies within our DNA.

The team, led by assistant professor of physiology and development biology Jonathan Alder, researched telomeres, which act as "caps" on the end of our chromosomes. It turns out that if you have a longer cap, you'll have a longer life expectancy. If that cap is short, you'll have a shorter lifespan.

Those telemeres, though, are also a key to disease. Shorter telomeres don't just predict a short lifespan, but are also indicative of certain illnesses, such as lung disease.

"When we are born, our telomeres are longer. As you get older, they shorten," said Alder. "What we have found is that if you look at individuals with lung disease, they have shorter telomeres than the rest of us."

Alder's research team is now studying genetic mutations that lead to short telomere lengths. When cells divide, the telomere grows shorter and shorter. This means that telomeres shorten as we age, and explains how they can tell us when we'll die. However, telomeres that already start out short have less of an advantage, and those shorter telomeres can also indicate potential disease.

Alder researches how, as well as why, this happens, as well as how to stop it. It's not as easy as lengthening telomeres, although we are capable of doing that now. That, however, comes with side effects, including cancer.

"This is a definite Goldilocks situation," said Alder. "Too little, you age prematurely; too much, you could get more serious diseases. You need to be just right."

In their current research, the team focused on emphysema and discovered that those who develop the disease tend to have mutations in the genes that control telomeres. Those mutations are also inheritable: shorter telomeres and emphysema are inherited from one generation to the next, with each generation getting slightly shorter telomeres and lifespans.

For smokers with shorter telomeres, the risk is even greater of contracting lung disease, as well as early death. This might also suggest why some smokers still live longer, though, in spite of statistics: perhaps their telomeres are longer than average.

Alder and his colleagues believe that telomere research is especially important in understanding lung disease, an illness that is the third most common cause of death in the U.S. However, shorter telomeres are also linked with bone marrow failure, liver disease and skin disease.