Tying Loose Ends

Over time our chromosomes – the tight bundles of DNA that contain all our genetic information, pictured in blue – start to deteriorate at the tips like a loose piece of string fraying at the ends. So like shoelaces have that little protective aglet, chromosomes have telomeres (highlighted here in white) at their extremes – repetitive sections of DNA that act as a buffer against the wear and tear of life, taking the hit each time a cell divides. They can do this, as Carol Greider – born on this day – co-discovered in 1984, because a molecule called telomerase rebuilds their scraggly ends each time. But eventually even telomerase tires of its duty and as its efficiency declines, so does a cell’s health, making telomerase pivotal to many diseases, and so crucial to medicine that it earned Greider a share of a Nobel Prize in 2009.

Written by Anthony Lewis

Anthony Lewis

Writer

Ant was the web editor in the early days of BPoD, and has since worked with the UK’s top science organisations as a writer and multimedia producer. He now splits his time between freelance work and managing multimedia at The Lancet.

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• Chromosome image by Hesed Padilla-Nash and Thomas Ried, National Cancer Institute, NIH
• Portrait courtesy of the US Embassy Sweden
• Images published on Flickr with a Creative Commons CC BY 2.0 (portrait) and a CC BY-NC 2.0 (chromosomes) Attribution