The chromosomes in every single cell are made up of DNA and shaped like strands, with a kind of protective cap at the end of each strand of DNA. Without this end protective cap, the DNA strands would chemically bond to other strands, i.e. the chromosomes would merge and that would be lethal for the cell. The structures that prevent this catastrophe are the telomeres. They were discovered in the 1930s but decades elapsed before someone decided to study them in any depth and since the late 1990s they have always been on the cutting edge of biology research. Biologists are often surprised by their amazing and unexpected complexity, and their health-related significance.
“The biology of telomeres is extremely complex and the more we discover the more we realise what remains to be discovered,” says Paula Martínez from CNIO's Telomere and Telomerase Group. “What surprises me most is the high number of factors we are finding that are essential to the preservation of telomeres and, above all, the precise coordination that is required between them all.” The fact that telomeres have been tightly preserved throughout the evolutionary tree — in most eukaryotes: vertebrates, plants and even unicellular organisms such as yeast — indicates their importance. In addition to preventing the merger of chromosomes, telomeres are needed to prevent the loss of genetic information each time a cell divides.