. SOURCE: National Geographic magazine . 'THE GREATEST JOURNEY' _Human Journey @ National Geographic Magazine_ (http://www7.nationalgeographic.com/ngm/0603/feature2/index.html) _http://www7.nationalgeographic.com/ngm/0603/feature2/index.html_ (http://www7.nationalgeographic.com/ngm/0603/feature2/index.html) . ----------------------------------------------------------------------------- . ALSO SEE: _Human Journey Learn More @ National Geographic Magazine_ (http://www7.nationalgeographic.com/ngm/0603/feature2/learn.html) _http://www7.nationalgeographic.com/ngm/0603/feature2/learn.html_ (http://www7.nationalgeographic.com/ngm/0603/feature2/learn.html) [excerpt]: . LEARN MORE: . Did You Know? . ..."Scientists who trace modern human origins often talk about a special kind of DNA, mitochondrial DNA (mtDNA). But do you know what mitochondrial DNA is? And do you know what mitochondria do? Mitochondria are tiny structures found within the cell that resemble grains of rice. They produce the energy that cells need to function, and they have their own small complement of DNA, containing just 37 genes in humans. Compare this to the human nuclear genome (the entire set of genetic instructions found within the nuclei of all the cells), which contains some 30,000 genes. But mitochondrial DNA is especially powerful for studying the ancestry of modern humans. While the nuclear genome is reshuffled with each new generation as the father's and mother's DNA recombine, mitochondrial DNA is passed directly from a mother to her children. As a result it preserves patterns of ancient markers that thelp scientists map the path modern humans have taken around the world. ..." —Alice J. Dunn . =============================================================== . RELATED LINKS: . The Genographic Project _www.nationalgeographic.com/genographic/_ (http://www.nationalgeographic.com/genographic/) A landmark study of the human journey. . A (personal) mtDNA View of the Peopling of the World by 'Homo Sapiens' _www.mcdonald.cam.ac.uk/genetics/mtDNAworld/one.html_ (http://www.mcdonald.cam.ac.uk/genetics/mtDNAworld/one.html) Follow this slide show along as Peter Forster traces the genetic evidence for how modern humans populated the Earth. . Journey of Mankind _www.bradshawfoundation.com/stephenoppenheimer_ (http://www.bradshawfoundation.com/stephenoppenheimer) Anthropologist Stephen Oppenheimer and the Bradshaw Foundation take you on a fascinating virtual tour of modern human's journey to populate the Earth. Explore maps with pop-up text and much more. . Kennewick Man Virtual Exhibit _www.washington.edu/burkemuseum/kman/virtualexhibit_intro.htm_ (http://www.washington.edu/burkemuseum/kman/virtualexhibit_intro.htm) Read more about Kennewick Man, his discovery, the controversy over who he was, how old he is, and to whom his bones actually belong. . ---------------- [end] .