Their findings are reported in the April 25 issue of the journal Scienc e .
Chromosomes are thin strands of DNA, the genetic material that determines hereditary makeup.
As the body ages, chromosome replication is hindered by the shutdown of an enzyme known as telomerase. Without telomerase, the ends of duplicated chromosomes get shorter and shorter. In cancer cells, however, telomerase is turned back on, and chromosomes are replicated without any loss in size. Knowing the protein that makes telomerase work might help drug companies develop anti-cancer medications, said Lundblad, assistant professor of molecular and human genetics. This type of protein copies genetic information from the virus and inserts it into the chromosomes of other cells, enabling the virus to spread.