Supporting the Origin of Modern Humans from Africa

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DNA analyses provide a solid foundation to explore possibilities in the evolution of the Homo species. The role of DNA analysis nowadays is essential to test hypotheses formulated by scholars in paleoanthropology. Since the advent of modern molecular genetic technology, the studies using the human DNA record have reveal a great amount of information related to human history and particularly the Homo sapiens history.

DNA (Deoxyribonucleic Acid) is giant molecule composed of pair of sequences carrying codons. In these codons is stored the genetic information of life. It shows how the individual came to be. It also shows the information about the parents of the individual, thus it establishes a clear correlation between generations.

DNA analysis is advantageous because each individual possesses a unique code, but at the same time it records information about ancestors. In this way, it is possible to reconstruct lineage history among populations. It is also possible to establish important evolutionary events such as migrations, coalescence, and also the timing of these events. By using methods from population genetics, scientists are able to explore these important issues and reconstruct the past. The most important work is to decode the encoded information. By comparing DNA sequences, scholars obtains important data related to human evolutionary history, such as the mutation of a gene, the variation among traits and the co-evolution of genes in particular populations. The fossil evidence, in conjunction with the genetic data, strongly indicates continuity between generations (Templeton 2002). Claims where made that a total replacement hypothesis will predict that all haplotype trees with coalescent times older than 100,000 years ago must be rooted in Africa. Researchers contrast this assumption with the observed data, which shows that about 90% of the trees appear to be rooted.

In conclusion, information from the fossil record and human DNA makes it clear that modern humans originated from Africa. Debate over the origins of modern humans has simmered among anthropologists for years, with one theory asserting that Homo sapiens migrated across the world from a single point in Africa. The other theory states that multiple populations of Homo sapiens independently evolved from Homo erectus in regions beyond Africa. The multiregional idea is identical to the Recent African Origin idea, except for its prediction that Europeans and Asians were part of the single population of origin and didn’t become extinct. In regards to the relationship between the different Homo species, the two divergent theories -the Recent African origin and the Multiregional origin- actually predict similar patterns in the genetic record. Genetic distance data through DNA analysis has been considered powerful evidence about the origin of modern humans (Relethford, 1999). DNA analysis shows that there is a degree of interbreeding, at least between Neanderthals and archaic H. Sapiens, but not between H. Sapiens and H. Rectus. To obtain a clearer picture of the evolution of modern humans, it is necessary to obtain more information from ancient DNA. With the advances in the field of ancient DNA, new possibilities will come to test the evolutionary relationships between humans and other homo during the Middle and Late Pleistocene.

Bibliography

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Aiello, Leslie C. 1993. The Fossil Evidence for Modern Human Origins in Africa: A Revised View. American Anthropologist 73-96.

Anton, Susan. C. 2003. Natural history of Homo erectus, American journal of physical anthropology, Vol. Suppl 37:126-170.

Relethford, J. 1999. Models, predictions, and the fossil record of modern human origins. Evolutionary Anthropology 8:7-10.

Stringer, C. B, and Andrews, P. 1988. Genetic and Fossil Evidence for the Origin of Modern Humans, Science 239(4846):1263-1268.

Wolpoff, M. H, with Hawks, J, and Caspari, R. 2000. Multiregional, not multiple origins. American Journal of Physical Anthropology, Vol. 112(1):129-136.

Robert, C. King, William, with D. Stansfield, and Pamela, K. Mulligan. A Dictionary of Genetics (7. ed) (New York: Oxford University Press, 2007).

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Templeton, A. 2002. Out of Africa again and again. Nature, 416:45-51.

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