Photo: Coming Soon: Your Personal DNA Map?

Email to a Friend << Back to Full Story


The chemical DNA (deoxyribonucleic acid) includes the instructions for all cells, the basic working units of every living thing. Twisted double strands of DNA are joined together by linked pairs of bases (A, T, C, and G) like the rungs of a ladder.

Specific combinations of bases are called genes. Their arrangements are codes for making distinct types of proteins. Joined together in long DNA strands, these genes form x- and y-shaped chromosomes, of which nearly all humans have 24.

A complete set of DNA for a species is called a genome.

Illustration courtesy U.S. Department of Energy

MOST VIEWED NEWS

PICTURES: 2012 Doomsday Myths Debunked

2012: Six End-of-the-World Myths Debunked

APOCALYPSE PICTURES: 10 Failed Doomsday Prophecies
NEWS FEEDS    After installing a news reader, click on this icon to download National Geographic News's XML/RSS feed. After installing a news reader, click on this icon to download National Geographic News's XML/RSS feed.

Get our news delivered directly to your desktop—free.
How to Use XML or RSS

ADVERTISEMENT

NATIONAL GEOGRAPHIC'S PHOTO OF THE DAY

Today's National Geographic Photo of the Day

• Today's Photo

• Download as Wallpaper

50 Drives of a Lifetime

National Geographic Traveler has scoured the globe for the world's most beautiful, interesting, and off-beat road trips. Dive in to get drive directions, quizzes, photos, and more.