Did Neanderthals and Humans Interbreed?

Did Neanderthals and Humans Interbreed?

Despite compelling evidence,1 a minority of paleoanthropologists still believe (as do some Christians) that Neanderthals made a genetic contribution to modern humans through interbreeding. If Neanderthals interbred with modern humans, then by definition, they must be human.

The case for Neanderthal-modern human interbreeding relies exclusively on morphological (structural, bodily) evidence. The first suggestion that humans and Neanderthals may have interbred came in 1999 when a team of paleoanthropologists reported a fossil find from Portugal (near Lapedo Valley) dated at 24,500 years ago. Researchers recovered the complete skeletal remains of a young male child from a burial site.2 At that time, these paleoanthropologists interpreted the anatomy of the “Lagar Velho child” to consist of a mix of modern human and Neanderthal features. From this, they concluded that these two species must be closely related and regularly met and mated with one another.3

In 2003, the same team of paleoanthropologists claimed to have discovered another modern human-Neanderthal hybrid. This specimen, recovered in Romania, consists of a single lower jaw that dates to about 34,000 to 36,000 years ago, a time when modern humans and Neanderthals appeared to co-exist in Europe. Again, these researchers interpreted the jaw and dental anatomy to be a mosaic of archaic, modern human, and Neanderthal features.4

Most paleoanthropologists dispute the interpretation of the Lagar Velho child and the Romanian finds as modern human-Neanderthal hybrids. Commenting on the Portuguese discovery, Ian Tattersall and Jeffrey Schwartz state, “The analysis . . . of the Lagar Velho child’s skeleton is a brave and imaginative interpretation, of which it is unlikely that a majority of paleoanthropologists will consider proven.”5 Most researchers think that the Lagar Velho child simply was either an unusually stocky modern human child or one with a growth abnormality and that the Romanian find represents a modern human jawbone with unusual features.

New research from the Max Plank Institute provides direct evidence that Neanderthals and modern humans did not interbreed.6 This work compared mitochondrial DNA recovered from four Neanderthals with mitochondrial DNA isolated from the remains of five modern human fossils. The Neanderthal and modern human specimens all date between 30,000 and 40,000 years ago and were recovered from the same geographical locations. Investigators readily recovered Neanderthal-type DNA from the Neanderthal specimens, but only human DNA in the modern human remains. Based on statistical analysis these workers concluded that it was unlikely that Neanderthals made any genetic contribution to the earliest modern humans. In other words, there is no conclusive evidence that Neanderthals and modern humans interbred nor any hint of a possible evolutionary connection.

  1. For references to the original scientific literature see Fazale R. Rana, “DNA Study Cuts Link with the Past,” Connections Vol. 2, No. 3 (2000), 3; Fazale R. Rana, “Neanderthal-To-Human Link Severed,” Connections Vol. 5, No. 2 (2003), 8-9.
  2. Constance Holden, “Ancient Child Burial Uncovered in Portugal,” Science 283 (1999), 169.
  3. B. Bower, “Fossil May Expose Humanity’s Hybrid Roots,” Science News 155 (1999), 295; Cidallia Duarte et al., “The Early Upper Paleolithic Human Skeleton from the Abrigo do Lagar Velho (Portugal) and Modern Human Emergence in Iberia,” The Proceedings of the National Academy of Sciences, USA 96 (1999): 7604-09.
  4. Erik Trinkaus et al., “An Early Modern Human from Pestera cu Oase, Romania,” The Proceedings of the National Academy of Sciences, USA 100 (2003): 11231-36.
  5. Ian Tattersall and Jeffrey H. Schwartz, “Hominids and Hybrids: The Place of Neanderthals in Human Evolution,” The Proceedings of the National Academy of Sciences, USA 96 (1999): 7117-19.
  6. David Serre et al., “No Evidence of Neandertal mtDNA Contribution to Early Modern Humans”, PLOS Biology 2 (2004): 0313-17.