<p>So&nbsp;the shortened part of chromosome means the&nbsp;repetitive part of telomere, by truncation occurred during cell divisionto protect genes on chromosomes.</p> <p>During the lifetime, as individual gets through cell division, the telomere ends become shorter and shorter.</p> <p>Then when all the telomeres are gone, cells stop the division,&nbsp;chromosomes remain only strands part, then die with aging.</p> <p>Because of this, telomere is pointed as a determining individual&#39;s&nbsp;aging and lifespan.</p> <p>However, telomeres can be also replenished by an enzyme called telomerase reverse transcriptase.</p>