This article is 'Free', but not Open Access. Further details on permissions applying to 'Free' articles is available at http://www.biomedcentral.com/about/reprintsandperm ; At the ends of eukaryotic chromosomes are telomeres, specialized structures with unusual properties. Specific efforts to compare sequences and properties of telomeres across species can reveal the generalities of telomere properties. ; Peer-reviewed ; Publisher Version