Telomeres have been shown to have unique structures that include short nucleotide sequences present as tandemly repeated units. The basic repeat sequence in all the species studied has the pattern $5'- T _{1-4}, A _{0-1} G _{1-8}-3'$. Same repeated sequence is found at the end of all chromosomes in a species. Not only this, same telomeres sequence may occur in widely divergent species (eg, Human beings, Neurospora and some acellular slime moulds).
Clusters of G residues in one strand and $C$ residues in the other characterise telomeric DNA. Also, in some species the telomeres terminate with a single-stranded DNA ($12-16$ nucleotides long) rich in guanine.