Telomeres, telomeric DNA, chromosomes

Telomeres are the structures at the ends of linear chromosomes. They preven t chromosome degradation and have some other functions. DNA-part of telomer es consists of monotonous repeats that are very conservative in the evoluti on. All the vertebrates possess the same telomeric repeats. It is the seque nce 5'-(TTAGGG)n-3'. Telomeric repeats are the astonishing DNA changing in a number of cellular generations: they become longer or shorter. The dynami cs of the telomeric repeat alterations in human cells is investigated bette r than in other species. There is very harmonious theory according to which the length of telomeric repeat is the measure of proliferative capacity of cells: longer telomeres correspond to the higher proliferative potential. However, the transfer of these relationships to the cells of other species of vertebrates gives some contradictions. All species except human have rel atively long telomeric repeats and relatively low proliferative potentials. Presented paper discusses this contradiction on the basis of our own and l iterature data and includes the attempt to prove the application of telomer e theory to the cells of different species.