Telomeres are the areas at the ends of chromosomes. Long double strand of DNA folds, forming a particular shape that is recognised as a chromosome. Each pair of chromosomes has its distinctive shape and size. However, all chromosomes have a characteristic feature - telomeres. They consist of repeated short sequences of nucleotides (building blocks of DNA) and do not encode any proteins. Telomeres protect genes that are located before them from been damaged during the cell divisions and protect chromosomes from "sticking" to each other. For this reason, telomeres can be described as a protective "caps" at the ends of chromosomes.
In order to start cell division, there should be done a duplication of DNA. Duplication process is conducted by several enzymes, one of them, DNA polymerase, leaves a short sequence at the end of DNA strand without replication. Thus, after every cell division cycle, chromosomes become a little shorter. If it were not for telomeres, valuable genetical information would be lost, and cell could not function. After each cell division telomeres get shorter and shorter until they disappear.
Yes, a special enzyme called telomerase can repair telomeres. Not all cells, however, have it. Telomerase is active in some stem cells and some white blood cells. This enzyme builds blocks of nucleotides at the ends of DNA after duplication and allows the infinite amount of cell divisions.
Each human cell has an average of 50 division cycles before it dies. Longer telomeres make the cells stay younger for the longer time. This fact opens the door to the anti-aging solutions and diagnostic techniques.
Some scientists argue that telomeres act as a "timer" for the cell death that stops them from becoming cancerous.
Thus, telomeres may hold an answer to the most difficult problems of aging and cancer prevention.
There is a clinical method developed for measuring the telomere length. It is called a Telomere Test. A blood sample is collected and analysed to find out the telomere length. Patient telomere score is then calculated. Higher score indicates the longer telomeres and the younger cells. Lower score can signal the presence of metabolic and degenerative diseases. Telomere test can provide valuable information on the level of the oxidative stress in your body.