Introduction: Telomere is the physical terminal of linear chromosomes composed of a non-coding sequence that protects the ends of chromosomes. Therefore, evolutionary process of telomerase, as the synthase enzyme of telomere, and its structure in various species should be discussed. The aim of this study was to collect the sequences of telomerase gene family and compare them in order to find motifs protected by this gene family and investigate the proximity of human TERT with other species using bioinformatics and computational methods. This study was performed on the 3 levels of protein, mRNA, and DNA. As the sequences of organisms have been increased, combining plants’ and animals’ data is a challenge. Also, more information about the structure of telomerase can help to find new ways to inhibit this enzyme in cancer.

Method: In this in silico study, species had at least 35% evolution similarity were selected from plants and vertebrates. Sequences were aligned using ClastalW program. Organisms’ evolutionary tree was drawn using MEGA5 software and protein motifs were detected using ScanProsite software.

Results: Proximity of human TERT with other spices was observed in C-terminal region. Amino acid parts preserved were detected and the reverse transcriptase domain was introduced as conserved functional motifs of all species at protein level.

Conclusion: Any removal or disturbance in RT-POL domain lead to enzyme deficiencies in all species. Also, the N-terminal region of TERT because of its high preservation in mammals, was introduced as an attractive target for inhibition of telomerase in breast cancer.