How humans spread around the world is still one of the mysteries in the history of mankind. Mitochondrial DNA has been a crucial line of experimental evidence in developing the current understanding of our genetic history. It has shed significant light in determining the population patterns and human migrations around the world. Studies of mitochondrial DNA have provided new insights in the way humans spread around the globe throughout time. Studies have suggested two major routes from East Africa through which humans exited Africa and colonized the globe. An early route through the tropical coast of the Indian Ocean to southeast Asia and Australasia 60-75 thousand years ago (kya) (Macaulay et al, 2005: 1034), and followed by a dispersal via the Levant into Europe and North Africa 40-45 kya (Atkinson et al, 2008: 472), these routes are often referred as “Out of Africa” migration.
Mitochondrial DNA has a lot of characteristics and features which makes its use very essential in determining the spread of humans throughout the world. Human mitochondrial DNA is solely inherited from mothers. A human’s mitochondrial DNA is the same as his mother’s mitochondrial DNA, which is the same as her mother’s mitochondrial DNA. Researchers can estimate a probability distribution of ancestors’ genes and migration paths through time if they are given a set of mitochondrial gene sequences. It is assumed that all mitochondrial DNA types in the human gene pool can ultimately be traced back to a common matrilineal ancestor that lived approximately 200,000 years ago in Africa.(Oven et al, 386) All human mitochondrial DNA can be traced back to a single mitochondrial DNA known as “mitochondrial Eve”, who lived in Africa a long time ago. Mutations are m...
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...s of Human Biology 37(3): 288-311.
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In this lab we amplified a region of DNA that is found in the mitochondria. Mitochondria have their own set of DNA. Mitochondrial DNA has “16,500 DNA building blocks (base pairs), representing a small fraction of the total DNA in cells. — Mitochondrial DNA contains 37 genes,” (Genetics Home Reference, NIH, 2014) The part of the DNA that we amplified was the D-loop region. This part of the mitochondrial genome is the origin of replication for the mitochondria. This part of the mitochondria is also “prone to somatic mutation, which are a type of non-inherited mutation.” (Genetics Home Reference, NIH, 2014) One’s mitochondrial DNA is only inherited from the maternal side. The reason why is because when “an egg cell is fertilized, nuclear chromosomes from a sperm cell enter the egg and combine with the egg’s nuclear DNA producing a mixture of both parents’ genetic code.” (Groleau, PBS, 2014) Since the mtDNA is the exact same as the mother’s one can trace back the lineage of their maternal side and trace from what part of the world they are descended from. The mtDNA contains a history storybook of the travels and nomadic paths their ancestors took before their creation. The purpose of amplifying this region of mtDNA is to trace back our lineage.
The Regional Continuity Theory, first developed in the early 1980s by Milford Wolpoff and a group of his students, asserts that after Homo erectus migrated out of Africa and moved into other portions of the Old World, local populations evolved slowly into modern humans through continuous interbreeding, genetic drift and natural selection, keeping the development of the species in the same main direction while maintaining adaptations to regional factors, but with many aspects common to all regions. The Regional Continuity Theory relies on fossil evidence far more than genetic evidence to support its claims, and cites anatomical features in Asian and European populations that carry from archaic humans to modern humans going back over 100,000 years. They, “point to the fact that many Europeans have relatively heavy brow ridges and a high angle of their noses reminiscent of Neanderthals. Similarly, it is claimed that some Chinese facial characteristics can be seen in an Asian archaic human fossil from Jinniushan dating to 200,000 years ago.”1 The merits of this theory suggest a broader expanse for evolution as a whole, suggesting that a wide array of factors, adaptations, and characteristics could feasibly create a viable species, as well as explaining so...
Multiregional Evolution: a theory that suggests modern humans evolved from individual populations of Homo erectus throughout Europe, Asia, and Africa during the middle of the Pleistocene epoch. Its supporters claim that premodern humans, Homo erectus, migrated from Africa to Europe and Asia and that gene flow amongst these population is responsible for the evolution of modern Homo sapiens (Jurmain, Kilgore, Trevathan, and Ciochon, 2013). This theory was developed by Wolpoff and his colleagues in the 1980s and is a topic they continue to explore today (2000). There are many who discredit this theory though. They believe that the multiregional model does not prove how all of these separate populations remained genetically similar to one another if they all evolved separately. The works of Pearson (2004) and Stringer and Andrews (1988) explore this opposing view to the multiregional model.
As sound as the regional continuity theory appears, it seems to be slightly lacking in genetic support. It appears that most of the support of this theory depends on fossil record which is important information but not stable evidence. The Out-of-Africa theory relies on more than just fossil evidence but a combination of fossils and genetic studies. It is important to use this information as well as the fossil records because “various interpretations of the transition are possible if researchers concentrate on only fossil evidence, while the mtDNA studies more strongly support replacement….the best approximation of the process still appears to be an African-based spread” (Nitecki and Nitecki, 1994). In a time where technology is becoming an integral part of society, it is easier to discover information that did not seem possible before.
Mitochondrial DNA (MtDNA) is inherited from the mother and passes down from female generations. For that reason, molecular biologists are able to link DNA from one person to a relative. I found it peculiar that albeit this specific genetic material is located in the mitochondria, which are housed within the eukaryotic cells and those cells have been reported to contain mostly introns; non coding sequences, this would be a reliable source for DNA.
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The majority of scientific work in genetics and genomic sequencing has been done in the last 155 years. In 1859, Charles Darwin published On the Origin of Species where he proposed evolution by natural selection. Evolution is the change of inherited characteristics of biological populations over successive generations.Yet, the principals of genetics required to explain how characters are ...
People have been trying to find the lost city of Atlantis for ever since Plato wrote about it, in his dialogues in 360 B.C. So many people have come to believe that they have found Atlantis, but the main question is could a civilization of that magnitude actually have existed in that time period. In our research we were able to prove that the Minoans, or the people who are said to have built the city of Atlantis, were able to make transatlantic voyages. But the thing is our research never showed them building any city of that magnitude. Yes they had the tools to, and the tools have been found in the Mediterranean area, where Atlantis is said to have been located, but no one has ever found conclusive evidence that the city ever existed. With all this being said, the evidence that we have presented, is that it really is more of just an educated guess, or judgment call on whether or not Atlantis existed. Our evidence shows that Haplogroup X has a very low regional concentration, the origins date back to 15,000 year ago, and mtDNA can prove all of this.
DNA Timeline: DNA Science from Mendel to Today. (2014). Retrieved May 29, 2014, from http://www.dnai.org/timeline/
... and therefore mitochondrial DNA is inherited only from the mother. Thus this DNA would be a unaltered sequence passed strictly along maternal lines and only changing by accident or mutation.
...G.E., Ioannou P.A., Scheer W.D., Herrera R.J. et al. 1994. Africa origin of human-specific polymorphic Alu insertions. Evolution Vol. 91: pp 12288-12292
Detecting signals of gene flow between Neanderthals and modern human ancestors can be challenging because the two groups share a common ancestor within the last 500,000 years. This is not any more concrete than the nuclear DNA sequence variation of present-day humans. The article goes on to say that Neanderthals share more genetic variants with present-days humans in Eurasia than with present day humans in sub-Saharan Africa (Green 1). This article is very scientific and dense. It becomes extremely hard to understand when it starts talk...
Throughout history, humans have asked many questions in regards to our own beginnings. Religion and science have examined what makes us who we are, and have tried to answer the enduring question of our own modern origins. Scientifically, theories are still debated as to when, where, and how modern Homo sapiens came to be what they are today. There are two major theories that now dominate the discussions of experts in the field of biological anthropology: the “Out-of-Africa” model and the “Multiregional” model of evolution. Stringer and Andrews argue that genetic and paleontological evidence supports a more recent Out-of-Africa model as opposed to a more drawn out Multiregional method that also incorporates gene flow (1263). In contrast, Wolpoff, Hawks, and Caspari claim that the Multiregional model is misunderstood, and clearing up discrepancies could bolster support for this theory instead (129). Pearson notes that while people like Wolpoff et al defend the Multiregional model, archaeological evidence seems to show that likely no intermixture between modern Homo sapiens and other archaic hominins happened during the spread of early Homo sapiens out of Africa (145). It is easy to see that the debate lingers onwards with an end not clearly in sight. This paper will further examine the arguments asserted by these authors and identify their core arguments, the data they use to support their arguments and determine which paper is the most convincing of the three.