 Through this research, Blackburn and collaborators noticed the replication system for chromosomes was not likely to add to the lengthening of the telomere, and that the addition of these hexanucleotides to the chromosomes was likely due to the activity of an enzyme that is able to transfer specific functional groups.The proposition of a possible transferase-like enzyme led Blackburn and PhD student Carol W. Greider to the discovery of an enzyme with reverse transcriptase activity that was able to fill in the terminal ends of telomeres without leaving the chromosome incomplete and unable to divide without loss of the end of the chromosome.This 1985 discovery led to the purification of this enzyme in lab, showing the transferase-like enzyme contained both RNA and protein components.