telomere
Reverse transcription also occurs with retrotransposons and during telomere synthesis in eukaryotes. Retrotransposons are self-replicating segments of eukaryotic genomes that use reverse transcriptase to move from one position in the genome to another via a RNA intermediate. A telomere is a region of repetitive noncoding nucleotide sequences at each end of a chromosome. These sequences protect the end of the chromosome from deterioration or from fusion with neighboring chromosomes. Each time DNA is replicated, small segments of DNA from the ends of the chromosome is lost. Telomerase is a reverse transcriptase that uses an RNA intermediate to elongate the 3' end of DNA strands in the telomere regions after each replication cycle.