The ongoing debate of whether
Homo neanderthalensis and
Homo sapiens are related remains unresolved, even though a substantial amount of evidence to disprove any relationship between humans and Neanderthals exists (Serre
et al ., 2004)
Homo neanderthalensis , also described as the legendary caveman was discovered in Neander Valley, Germany in 1856 and was initially thought to have been an ancestor to modern man. It is assumed that humans and Neanderthals shared a common ancestor about 500 000- 600 000 years ago, probably
Homo erectus (Krings, 1997). Some scientists still believe that Neanderthals are a subspecies of
Homo sapiens and that they shared genetic information either by inbreeding or evolving into humans, while others believe that classifying Neanderthals as a subspecies of humans robs them of evolutionary distinctness (Tatterstall & Schartz, 1998).
DNA evidence suggests that
Homo sapiens evolved in Africa (The out of Africa theory) about 200 000 years ago, and because Neanderthals were found in Europe, there was probably no relation between the two species, though some paleoanthropologist consider interbreeding between humans and Neanderthals due to cohabitation for centuries (Krings, 1997).
Neanderthals differ morphologically, behaviorally and genetically from humans (Tattersall & Schwartz, 1998). Neanderthals had a more sturdy and robust build than humans, and even had a larger brain (Tattersall & Schwartz, 1998). The skulls of modern human were compared three dimensionally to the skulls of Neanderthals as well as to those of other primates and results yielded from statistical analysis illustrated that Neanderthals were indeed a breed apart and unrelated to modern humans (Rincon, 2004).
Mitochondrial DNA from Neanderthals are significantly different from humans, but were compared to other Neanderthals proved that the mtDNA was similar (Serre
et al ., 2004).
Genetic results, however, do not rule out the possibility of a small contribution to the modern human gene pool by the Neanderthals. Sequences could have been eliminated through processes such as genetic drift or by humans contributing extensively to the Neanderthal gene pool (Serre
et al ., 2004).Another possibility includes the contamination of fossil DNA with that of modern human DNA, even though the chances are very small. In order to minimize contamination error, scientists compared mtDNA of four Neanderthal to human mtDNA, and results showed that the genetic material of the Neanderthals were similar and differed significantly from the human mtDNA (Serre
et al ., 2004).
It is impossible to tell without a doubt whether the two species are in fact related or interbred, but according to morphological, behavioral and genetic evidence, it is suggested that they are two distinct species that cohabited the earth and did not interbreed (Kring, 1997). If interbreeding had occurred, it was between Neanderthal men and modern women, therefore no mtDNA exchange occurred, which is very unlikely (Kring, 1997).
References :
Serre D, Langaney A, Chech M, Teschler-Nicola M, Paunovic M, Mennecier P, Hofreiter M, Possnert G, and Pääbo S (2004) No Evidence of Neandertal mtDNA Contribution to Early Modern Humans. Plos Biology: 2(3): e57
Krings M (1997) In our genes? Economist 344(8025): 71-72.
Rincon P (2004) Neanderthals 'not close family'
http://news.bbc.co.uk/2/hi/science/nature/3431609.stm .
Tatterstall I, SchartzJH (1998) Morphology, paleoanthropology, and Neanderthals. Anat Rec: 253(4): 113-7.
