Are modern humans biologically related to Neanderthals - Essay Example

Are modern humans biologically related to Neanderthals? The Neanderthals were first discovered in the Neander Valley in 1856, and they represent the origin of modern humans. For 200,000 years, the Neanderthals adapted to the glacial climates of Northwestern Eurasia and were replaced by species similar to modern human about 30,000 to 40,000 years ago. They represent the genus Homo. The Neanderthals also have characteristics that represent both male and female sexes, and are chronologically representative of ages. The Neanderthal cranium had certain characteristics; including long cranial vault, a mandible without a chin, and an occipital bun. After their discovery, Neandertals have always been associated with human variation. Human evolution has always been associated with interbreeding of Neandertals with other species. This is supported by genetic evidence from the study of human evolution. To answer the question of whether modern humans are biologically related to Neanderthals, two journal articles will be analysed. These articles are: “How Neandertals Inform Human Variation” by Milford H. Wolpoff, and “Neanderthals and the modern human colonization of Europe” by Paul Mellars. Mellars (2004) suggests that the replacement of the Neanderthals about 40,000 years ago can be associated with the appearance of modern human artifacts in East and Southern Africa, and involved little, if any, interbreeding between the two populations. The article suggests that studies on DNA structure of modern humans and ancient DNA of Neanderthals reveal that there is no relationship between the modern humans and the Neanderthals. Mitochondrial and Y-Chromosome DNA patterns representing female and male lineages respectively have been studied. An analysis of seven Neanderthal specimens provided some segments of mitochondrial DNA which were radically dissimilar or different from all modern humans in Europe or any other parts of the world. Mellars (2004) therefore concludes that there was no or little interbreeding indigenous Neanderthals and expanding modern populations in Europe. The result of the studies shows that the modern humans originated from Africa about 150,000 years ago and were dispersed to other parts of the world where they replaced Neanderthals rather than interbreeding with them. This is clearly evidenced by the discovery of skeletal remains of anatomically modern humans in different parts of the world. Anatomically modern humans were discovered in Africa while distinctively modern humans were discovered in Europe and Asia. The anatomical modern humans existed 150,000 years ago while the distinctive modern populations existed 40,000 years ago. Archaeological evidence also shows that Aurignacian technologies were spread across central, southeastern and Western Europe through the dispersion modern human from Africa. The Aurignacian technologies of modern human emerged directly from the Neanderthal technologies; indicating that the Neanderthals of Asia and Europe associated with new populations from Africa. Another group of the modern human was dispersed along the coastal Mediterranean of Europe. Neanderthal genes disappeared in Europe because there was a direct competition between the Neanderthals and the modern humans in terms space and resources. The modern humans won because they had more complex technology and organization. According to Mellars (2004), there must have been great contact and interaction between modern populations expanding into Europe and the indigenous Neanderthals across Europe. These interactions were mainly behavioural. The study of mitochondrial and Y-Chromosome DNA pattern indicates that fully modern humans derived from Africa were dispersed across Europe but these biological studies do not indicate any interaction between the Neanderthals and the modern humans biologically. However, the ability of Neanderthals to adopt some technologies of the modern human from Africa indicates that they had brains that were identical to modern humans. Therefore, although there is genetic evidence that there were no biological relationship between modern humans and Neanderthals, the possibility of interbreeding between the two hominid groups cannot be ruled out; although it could be to a small degree. There could also be divergence of neurological and genetic structures over the 300,000 years of history. Wolpoff (2009) provides a different view by suggesting that interbreeding was an important aspect of human evolution, and anatomical difference and gene flow restriction could indicate that Neanderthals were indeed humans. Like Mellars (2004), Wolpoff suggests that there is variation in the genetic ancestry of Neanderthals and modern human. Studies of Mitochondrial and nuclear genome demonstrate a variation in the genetic makeup of Neanderthals and modern humans. Wolpoff uses theories from past studies to argue that the use of mitochondrial DNA in the study of Neanderthals is no longer important because Neanderthal haplogroup does not exist anymore, and selection usually affects the evolution of mitochondrial DNA. However, hominids from Eurasia showed an indication of Mitochondrial DNA related to Neanderthals. This shows that the Neanderthals were spread across Eurasia. There is also an evidence of selective sweep which involved the study of a mitochondrial genome of Vindija 33.16 Neanderthal. This genetic study indicated that one of the genes had four amino acids found in human’s Mitochondrial DNA. The same amino acids were also found in other primate species. Therefore, variation between humans and Neanderthals were caused by recurrent selection. Wolpoff (2009) speculates that such results are only possible if the existing Mitochondrial DNA replaced the Neanderthal lineage due to selection. This article also suggests that the study of alleles indicate the presence of modern alleles in Neanderthal samples. For example, study on FOXP2 gene which represents human language. The presence of the gene in Neanderthal samples could be due to interbreeding between humans and Neanderthals, although the direction of interbreeding is not certain (Wolpoff, 2009). However, there are arguments against this evidence which suggest that the samples from the Neanderthals could be contaminated. Furthermore, there could be a possibility that the FOXP2 could be shared between Neanderthals and modern humans due to descent of a common ancestor between the two populations. Wolpoff (2009) suggests that there is an evidence of archaic Neanderthal alleles in modern human populations too. The study of nuclear genetic variation in modern humans helps in avoiding the contamination problem. Alleles which were present in Neanderthal and other archaic populations were also found to be present in modern humans; but this came to be under positive selection. Wolpoff (2009) suggests that positive selection indicates a few interbreeding events involved. Wolpoff (2009) concludes by saying that there is no human race. This means that there are no distinct types of humanity and taxonomy for humans. The modern humans are instead characterized by subspecies which combine human groups in terms of anatomical similarity and geographic differences; hence forming taxonomic grouping. In this regard, Neanderthals are considered as the subspecies of Homo sapiens. There is variation between humans and Neanderthals, and the Neanderhal genes have been dispersion through selection to populations with descendants. The FOXP2 genes entered the Neanderthal population through selection – and entered the human genome. This shows that gene flow between humans and Neanderthals was two-way; and Neanderthals are considered as human subspecies. Therefore, it is true to say that there was a biological relationship between modern humans and Neanderthals. In conclusion, it is clear that the two articles provide different viewpoints concerning the biological relationship between modern humans and Neanderthals. Mellars (2004) suggests that there were behavioural interactions and relationships between Neanderthals and modern humans in Europe after the modern humans dispersed to Europe from Africa and met the Neanderthals in their indigenous home. However, genetic studies revealed that there was little or no interbreeding that existed between the two populations. On the other hand, Wolpoff (2009) suggests that evidence has indicated a biological relationship between modern human and Neanderthals. This was seen through experiments that involved modern human alleles that were also found in Neanderthals. The article also suggested that Neanderthals were a subspecies of humans and the two populations interbred in both directions. References list Mellars, P. (2004). Neanderthals and the modern human colonization of Europe. Nature, 432 (25), 461-465. Wolpoff, M.H. (2009). How Neandertals Inform Human Variation. American Journal of Physical Anthropology, 13, 91-102. Read More