Controversies in Science/Was there a mitochondrial Eve?/A critique of Whole-mtDNA Genome Sequence Analysis of Ancient African Lineages

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We Originated in Africa & We All Originated From The Same mtDNA[edit]

Human DNA has been found to originate in Africa, therefore the human population around the world originated in Africa from the same mitochondrial DNA. [1]

Two decades ago, based strictly on genetic research, scientists discovered that all humans have a common ancestor. This ancestor was a woman in Africa also known as 'Eve'. [2]

With the theory of Mitochondrial Eve we should have all originated from one woman, and an experiment done on mitochondrial DNA; it was traced back 200,000 years ago. It is suggested that; if mitochondrial eve is true then there were only derived from a few of individuals living; causing a bottle neck effect on human DNA. If there had of been interbreeding with other species we would be able to see their DNA; however there was no mitochondrial DNA of Neanderthals[3]

It is difficult to say that human DNA has been found to originate in Africa, at best we can say it likely did, but there is evidence to consider to the contrary. Relethford's study that the Mitochondrial Eve hypotheses neglects to account for intermarriage and migratory patterns, and matrix modelling can prove this.[4] As such it's not possible to extrapolate that the entire human population evovled from a common African ancestor.Ixby, Not what you expect. (talk) 01:39, 28 March 2012 (UTC)
Our argument can be supported by this groups findings and research - "The Coalescence Theory has proven that genetic behavior has a common ancestor from one original mother dated back around 200,000 years ago. Through the rigorous study of mtDNA, it is mathematically proven to show organisms are maternally transmitted and have common genetic behavior. Essentially, humans have mutated from one being to the next carrying the same gene through each generation[5].

Methods[edit]

Researchers took blood samples from humans worldwide, as well as samples from individuals in the east part of Africa where they hypothesize where human beings originated from. In addition, samples from neanderthals were also taken to compare the results. The mitochondrial DNA was harvested in labs and used to compare and contrast with the blood samples taken from the other areas of the world.[1].

Three different sets of samples were selected by choosing Tanzanians who were diverse both culturally and linguistically to make a total of five groups. For the second group, 25 tanzanian sample groups were sequenced to represent the mtDNA that was ancient and included L0, L1, and L5 haplogroups. For the third group ten samples from SAK, 9 were sequenced belonging to mtDNA haplogroups L0d and L0k.[1].

Dna Originates In Africa


Results[edit]

Various ethnic groups from Tanzania, Africa with mitochondrial DNA genomes were studied in order to represent haplogroup lineages, or ancestral descents compared with mitochondrial DNA genomes of diverse groups around the world to show variables in inheritable traits. The amount of mitochondrial DNA among Tanzanian’s was more than twice that of non-Africans. Significant trait diversity was noted in the global data set but the Tanzania population carried strong characteristics of similar nature that was not found in any other group involved with this study. An mitochondrial DNA tree was created breaking these two groups down through branches stating various characteristics pertaining to each group. Several notable characteristics of the haplogroups are Africa specific showing monophyletic properties, meaning they are all descending from a single ancestral group. To further resolve the evolutionary history of ancient mitochondrial DNA haplogroup lineages these two genomes were further broken down into smaller sub-divisions focusing on specific beings of particular locations, one being of Tanzania and the other composed of the global panel. This only further supported mitochondrial DNA of African’s belonging to the lowest possible level of haplogroups ancestry of the human mtDNA gene tree. An algorithm was applied to the data from these findings calculating components of the gene tree. The estimate resulting was very close to the age of the earliest modern humans estimated from fossil data and also close to the results of other early mitochondrial DNA diversity studies. All in all this analysis suggests the origin and diversification of modern humans today was greatly affected by the continuous imperative role played by populations in eastern Africa.[1].

After taking samples from neanderthals; the results showed they had mitochondrial DNA, however they were different from humans. Since we can only trace back 196,000 years ago it indicates neanderthals and humans did not mate as there mitochondrial DNA is different. If the mitochondrial DNA been similar we would be able to trace it back further, however this was not the case [6]

These points are valid, however, it is not looking at the whole picture. Although the study I'm referring to uses a computer generated model, the results from it cannot be ignored. The method used is called the Monte Carlo model which is a simulation dispersing individuals. The simulation showed individuals moving at the pace of a parent and child walking together which worked out to 320 km2/generation. There were a total of 101 locations and they were spaced 115 km apart and distance was roughly the distance from Ethiopia to China (11,500 km). The simulated population size was 10,100 individuals, which is the common estimate of the long-term effective population size of humans. Based on this simulation the nuclear genome disproves the “Recent Africa Origin” theory because it shows how mitochondrial DNA can occur in a multiregional world and that 80% of homo sapiens nuclear loci have DNA from non-African archaic humans. --Randana (talk) 00:34, 11 April 2012 (UTC)

References[edit]

  1. 1.0 1.1 1.2 1.3 Gonder, M., Mortensen, H., Reed, F., de Sousa, A., & Tishkoff, S. (2006). Whole-mtDNA genome sequence analysis of ancient African lineages. Molecular Biology and Evolution, 24(3), 757-768. doi:10.1093/molbev/msl209 http://mbe.oxfordjournals.org/content/24/3/757.full.pdf+html
  2. Samira, Unknown. Humanity ORIGINATED from AFRICA http://www.imperialafrica.com/sitebuildercontent/sitebuilderfiles/Nubians-III.pdf
  3. http://books.google.ca/books?hl=en&lr=&id=jKbyupyw5TQC&oi=fnd&pg=PA89&dq=mitochondrial+eve+graphs&ots=LehhbHt0Rj&sig=qe53L2qPpoWr29XssKq9AKG8Q8o#v=onepage&q=mitochondrial%20eve%20graphs&f=false
  4. Relethford, J. (2001) Absence of Regional Affinities of Neandertal DNA With Living Humans Does Not Reject Multiregional Evolution, American Journal of Physical Anthropology 115, 95–98 http://ejscontent.ebsco.com/ContentServer.aspx?target=http%3A%2F%2Fonlinelibrary.wiley.com%2Fresolve%2Fdoi%2Fpdf%3FDOI%3D10.1002%2Fajpa.1060
  5. De Oliviera, P., M., C., De Oliviera, S., M., Radomski, J., P. (2001). Simulating the mitochondrial dna inheritance. Theory in Biosciences, 120(2), 77-86. doi: 10.1007/s12064-001-0008-x Retrieved from http://library.mtroyal.ca:2088/content/j28133773h623025/abstract/
  6. mbe.oxfordjournals.org/content/24/3/757.full.pdf+html