Some are thought to contain names and addresses, while others contain affectionate letters.

BBC: 'Entire streets' of Roman London uncovered in the City

Another advantage: These stretches can also be made to contain all the DNA letters that occur between genes.

FORBES: Magazine Article

Several more cases of using DNA sequencing, which reads out the 6 billion DNA letters that contain the protein recipes that make one person different from another, to understand the cause of disease have been published.

FORBES: Sequencing A Child's DNA -- And Convincing An Insurance Company To Pay

But as you guys know, these letters often look different, contain different information and often, frankly, do a poor job of making clear how much a student will receive in terms of grants and scholarships, and how much they'll have to borrow in terms of student loans.

WHITEHOUSE: Press Briefing