Telomers and Cell Aging

Telomers, and their length, have recently been implicated as a risk factor for heart disease. This short article discusses just what this important parts of your genetic makeup are - and sheds some light upon them as the secret of aging.

A mammalian cell,‭ ‬in general,‭ ‬reproduces by a process of division termed mitosis.‭ ‬This,‭ ‬in theory,‭ ‬provides for an infinite supply of cells and there should be no need for aging.‭ ‬Unfortunately,‭ ‬each time a cell divides it is possible that there will be mistakes in the copying of DNA,‭ ‬termed mutations.‭ ‬Most mutations within a mature tissue are

harmless,‭ ‬however there others can cause serious disease‭; ‬most notably cancer in which cells divide without proper restraint.‭ ‬With each division the chance of a problematic mutation increases and so,‭ ‬over the course of evolution,‭ ‬a limit has developed upon the number of times a cell divides.

At one end of a chromosome is located a long region of repetitive DNA termed the telomere.‭ ‬This acts as a buffer during replication because the DNA polymerase complex which duplicates DNA is unable to deal with the very tail of the DNA molecule‭ – ‬much as a desktop printer is often unable to print to the very bottom edge of the page.

Each time the cell is copied some of the telomere region is omitted,‭ ‬making the overall length of the chromosome shorter.‭ ‬As the telomere doesn’t contain important genetic information this loss does not cause a problem to the cell,‭ ‬but it does provide a fool-proof way of counting the number of divisions that have taken place.‭ ‬When the telomere runs out then the cell will no longer divide,‭ ‬the limiting number of divisions being termed the Hayflick limit.‭ ‬A reduction of cell metabolism has also been linked to telomere length.
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