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Human relationship to Neanderthals remains murky

Oct. 21, 2013
Courtesy of Indiana University 
and World Science staff

Al­though some sci­en­tists have treated as set­tled the ques­tion of how mod­ern hu­ma­ns are re­lat­ed to Ne­an­der­thal peo­ple, it’s not, a new study says.

The re­search, pub­lished this week, con­cludes that no known crea­ture is the last com­mon an­ces­tor of both.

The search for a com­mon an­ces­tor link­ing mod­ern hu­ma­ns with Ne­an­der­thals—stocky, tough peo­ple who lived in Eu­rope thou­sands of years ago—has at­tracted plen­ty of re­search in­ter­est. 

In the new work, sci­en­tists ex­am­ined fos­sil teeth, look­ing for a crea­ture that fit the ex­pected pro­file of an an­ces­tor of Ne­an­der­thals and mod­ern hu­ma­ns. They stud­ied about 1,200 mo­lars and premo­lars from 13 spe­cies or types of ho­m­i­n­ins—hu­ma­ns and hu­man rel­a­tives and an­ces­tors. 

They con­clud­ed that none of the crea­tures usu­ally pro­posed as a com­mon an­ces­tor is a good match. These hu­man forms in­clude fos­sils dubbed Ho­mo hei­del­ber­gen­sis, Homo erec­tus and Homo an­te­ces­sor

“None of the spe­cies that have been pre­vi­ously sug­gested as the last com­mon an­ces­tor of Ne­an­der­thals and mod­ern hu­ma­ns has a den­tal mor­phol­o­gy [shape] that is fully com­pat­ible with the ex­pected mor­phol­o­gy of this an­ces­tor,” said Aida Gómez-Robles, lead au­thor of pa­per on the work and a re­searcher at George Wash­ing­ton Uni­vers­ity in Wash­ing­ton, D.C.

The in­ves­ti­ga­tors al­so con­clud­ed that the lines that led to Ne­an­der­thals and mod­ern hu­ma­ns branched apart nearly a mil­lion years ago, much ear­li­er than stud­ies based on mo­lec­u­lar ev­i­dence have sug­gested.

Hu­mans are be­lieved to be de­scen­dants of apes and, more re­cent­ly, of Ho­mo erec­tus, one of the first spe­cies con­sid­ered to be a type of ac­tu­al hu­ma­n. Ne­an­der­thal peo­ple are thought to be rel­a­tives of mod­ern man who arose lat­er, and died out around 28,000 years ago.

The new study is pub­lished on­line this week by the jour­nal Pro­ceed­ings of the Na­t­ional Acad­e­my of Sci­ences.

Answers to the ancestry question could come from studying hom­i­nin fossils from Af­rica, the researchers say. But the Afri­can fos­sil record from the era of int­erest is sparse. “The study tells us that there are still new hom­inin finds waiting to be made,” said study co-auth­or P. David Pol­ly, of In­diana Uni­versity Bloom­ing­ton.


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Although some scientists have treated as settled the question of how modern humans are related to Neanderthal people, it’s not, a new study said. The research, published this week, concludes that no known creature is the last common ancestor of both. The search for a common ancestor linking modern humans with Neanderthals—stocky, tough people who lived in Europe thousands of years ago—has attracted plenty of research interest. In the new work, scientists examined fossil teeth, looking for a creature that fit the expected profile of an ancestor of Neanderthals and modern humans. They studied about 1,200 molars and premolars from 13 species or types of hominins—humans and human relatives and ancestors. They concluded that none of the creatures usually proposed as a common ancestor is a good match. These human forms include fossils dubbed Homo heidelbergensis, H. erectus and H. antecessor. “None of the species that have been previously suggested as the last common ancestor of Neanderthals and modern humans has a dental morphology [shape] that is fully compatible with the expected morphology of this ancestor,” said Aida Gómez-Robles, lead author of paper on the work and a researcher at George Washington University in Washington, D.C. The investigators also concluded that the lines that led to Neanderthals and modern humans branched apart nearly a million years ago, much earlier than studies based on molecular evidence have suggested. Humans are believed to be descendants of apes and, more recently, of Homo erectus, one of the first species considered to be a type of actual human. Neanderthal people are thought to be relatives of modern man who arose later, and died out around 28,000 years ago. The new study is published online this week by the journal Proceedings of the National Academy of Sciences.