Paleontological   evidence   indicates  that  the  Neanderthals,  Homo
   neanderthalensis,  lived  in Europe and western Asia from some 300,000
   to 30,000 years ago. For at least 30,000 years, Neanderthals coexisted
   with  anatomically  modern  humans  (H.  sapiens)  in  several  areas.
   Questions  about Neanderthals and modern humans remain unanswered: (1)
   Can Neanderthals be regarded as direct ancestors of modern humans? (2)
   Did Neanderthals and H. sapiens interbreed, so that descendants of the
   Neanderthals  are  alive  today?  Or  did the Neanderthals die off and
   become extinct?

   To  resolve  these issues, several groups have focused their attention
   on  the recovery and analysis of DNA extracted from Neanderthal bones.
   In  1997,  Svante  Pääbo,  Matthias  Krings,  and  their  colleagues
   extracted  fragments  of mitochondrial DNA from a Neanderthal skeleton
   found  in  Feldhofer  cave near Düsseldorf, Germany. After confirming
   that   they  had  indeed  isolated  Neanderthal  gene  fragments,  the
   researchers  placed  the  Neanderthal sequences on a phylogenetic tree
   together  with  sequences  from  more  than 2000 modern humans [Figure