Introduction
Available literature demonstrates that the discovery of genetic principles in the 20th century, along with the discovery of methodologies that could be used to extract and characterize ancient DNA specimens, provided the needed impetus for the field of physical anthropology to undergo a major shift in its approach and practice (O’Rourke et al 217; The International History Project para. 15).
After almost three decades of research in human genetic information, the broad consensus among physical anthropologists is that DNA research have indeed changed and broadened our understanding on various biological aspects that are unique to human beings, particularly in the interpretation of physical differences among races, determining the place of mankind in nature, and in undertaking comparative analysis of human beings with other primates (Broida 12). This paper purposes to critically evaluate how discoveries in DNA research continue to influence the field of physical anthropology.
DNA: A Brief History
Research into the double-stranded molecule that contains the genetic code, and which is commonly referred to as DNA (deoxyribonucleic acid), demonstrates that this molecule is not only fundamental to all cellular activities, but it is fundamental to life itself (Jurmain et al 53). Indeed, DNA is the very basis of life by virtue of the fact that it directs and controls all cellular activities, including how cells divide to sustain growth in both primates and non-primates. This implies that DNA is a fundamentally important concept in the process of understanding how traits are inherited – one of the major interest areas of physical anthropology.
However, current literature demonstrates that “…the exact physical and chemical properties of DNA were unknown until 1953, when, at the University of Cambridge in England, an American researcher named James Watson and [other] three British scientists…developed a structural and functional model of DNA” (Jurmain et al 53). It is impractical to exaggerate the significance of this particular discovery because it not only entirely revolutionalized the fields of biology and medicine, but it forever changed our understanding of biological and evolutionary perspectives, which are of critical importance to the field of physical anthropology.
Despite the above and other subsequent achievements in DNA research, the major contact point between DNA and physical anthropology came in 1984 when a research study conducted by Higuchi and colleagues was able to extract and characterize DNA in ancient specimens of non-human nature (O’Rourke et al 217). This and other discoveries in DNA research will be discussed in detail in subsequent sections of this paper. Of great importance, however, is the realization that DNA has been instrumental in the process of cell division – a particularly important process in the field of physical anthropology since it enables anthropologists to evaluate how organisms grow (Jurmain et al 55).
Another important component of this discussion, particularly in the light of ancient creatures, is the realization that advancements in DNA research have enabled us to establish linkages between present forms of life in human and non-human primates and other mammals on the one hand and ancient forms of life on the other hand (Jurmain et al 55). This knowledge has been instrumental in not only understanding the concept of evolution, but also in establishing a basis for an objective discussion of species that have already become extinct because of competition for scarce resources and disease susceptibility, among others.
Examining how DNA has changed the Field of Physical Anthropology
It is indeed correct to argue that contemporary DNA research has not only changed the field of physical anthropology in major ways, but it continues to alter and broaden our understanding and perceptions in a number of areas that are considered critical to this particular field. Physical anthropology, in its most rudimentary form, concerns itself with human evolutionary perspective, physical development of the human species, human behavioral adaptations, and racial mapping (McBrinn 296).
In this perspective, it can be argued that DNA research has enabled us to learn and understand how the human race has changed through time to become what it is today, primarily because of the fact that it is through DNA replication that cells multiply and, in turn, enable human beings and other organisms to grow and wounded cells to heal (Jurmain et al 55).
It is through DNA research that we are now able to comprehensively understand how genes (units within sex cells such as the sperm and egg) are able to convey explicit hereditary characteristics from one generation to the next (The International History Project para. 16), thereby not only understanding the evolutionary and physical development of the human species, but also their racial and behavioral adaptations as well (Weaver & Roseman 680). Contemporary DNA research has given anthropologists a new platform for understanding how inherited characteristics or traits influence human variations and divergences between races (Long et al 25). Today, it is clear that alterations in DNA ultimately lead to variations between species.
In evolutionary perspectives, it is clear that DNA research has changed the theory of progressive evolution, in large part due to the presenting evidence from DNA and genetic studies that there may be a possibility of the concept of genetic reversals in the physical development of both human and non-human species; that is, “…reversions back into traits and characteristics thought to be discarded in the hereditary process” (The International History Project para. 16). Knowledge about genetic reversions, which has been generated through recent advances in DNA research, facilitates an all-encompassing understanding of vertebrate development, mutations, and human disease such as epidermolytic hyperkeratosis.
The studies of fossil remains and behavioral adaptations of other primates have largely become objective and scientific – courtesy of the recent advancements in DNA research (Krogman 12). It is important to first underline the fact that the studies of fossil remains and behavioral adaptations form a critical constituent of physical anthropology. Through DNA research, we are now able to understand why and how “…humans have many unique traits and characteristics that are thought to be adaptations, such as language, encephalized brains, bipedal locomotion, and opposable thumbs with precision grip” (Muehlenbein 253).
Here, it is also important to note that advancements in DNA research has enabled the use of DNA markers to comprehensively examine the differences between humans and non-human primates in the pursuit of understanding human behavioral adaptations and the source of our uniqueness as humans. Indeed, these advances in DNA research have enabled anthropologists, scientists and other researchers to undertake phylogenetic comparisons between genes of the human kind and their orthologs (genes that are recognizable based on descent) in apes such as chimpanzees with a view to comprehensively investigate the bases for human uniqueness and behavioral adaptations (Muehlenbein 253; O’Rourke et al 230). It is needless to say that such investigations, which are critical to the field of physical anthropology, would not have been possible in the absence of contemporary DNA research.
Lastly, it is worth mentioning that contemporary DNA research have considerably altered the field of physical anthropology with regard to understanding issues of reproduction, sexual orientation, and development in human and non-human primates. Owing to reported advances in DNA research, reproduction and development, whose relationships with each other has previously been exceedingly ambiguous, are now perceived to be intricately related to the process of cell division. It is through the in-depth understanding of DNA and genetics that we now know that while the body at all times is composed of cells, reproduction and development – two important concepts evaluated in physical anthropology – are the results of two diverse kinds of cell division (Long et al 27).
To explain the concepts, “…mitosis [is] the process by which cells divide into two identical cells, and the body thereby grows; and meiosis [is] the process by which sperm and egg cells are produced to transmit genetic information into the next generation of organisms” (Marks 15). This knowledge has been widely used in the field of physical anthropology to develop a wider understanding on the bases of such social systems as the family, ethnic group and race. The knowledge has also been extensively used to explain genetic variations, particularly after scientific evidence was adduced to the fact that each egg or sperm contains half the amount of genetic information of ordinary cells, and the genetic information carried by each of these cells greatly differs (Mark 15).
Important Discoveries in DNA Research
The convergence of technology have provided an enabling environment for researchers engaged in DNA research, especially in the field of physical anthropology, to come up with important breakthroughs. It is important to note there is no fine distinction between important discoveries in DNA research from other disciplines such as biology and neuroscience, and discoveries related to physical anthropology as scientific knowledge is not only generalizable, but objective as well (Weaver & Roseman 678). In 1953, for instance, scientists at the University of Cambridge, England, were able to delineate the exact physical and chemical properties of the DNA (Jurmain et al 53).
Although this was a largely scientific discovery in nature, it is an important discovery in the field of physical anthropology by virtue of the fact that it formed the bases by which later-day anthropologists came to understand a multiplicity of issues, including the uniqueness of the human species when compared to non-human primates and other mammals, evolutionary perspectives, and racial relations, among others (O’Rourke et al 220).
Perhaps one of the most important discoveries in DNA research was made in 1984, when a group of researchers, led by Higuchi, successfully extracted and characterized DNA of ancient specimens originating from non-human material. In this particular research, researchers “…identified nucleic acids from a museum specimen of the extinct quagga and showed its phylogenetic affinity to modern zebra (O’Rourke et al 217).
This particular discovery has enabled modern-day anthropologists to use bones, skulls, and other parts of the body of ancient animals, including humans, to reconstruct history and adaptability of these ancient organisms with a view to objectively know how modern creatures have evolved over time. It is important to note that the DNA of ancient specimens has also been extensively used in modern times to address critical issues in human population history; that is, address the underlying question of ‘where we come from’ (O’Rourke et al 217; Long et al 27).
Another important discovery in DNA research came in 1985 when an anthropologist named Paabo succeeded in obtaining DNA sequence data from a 2400-year-old mummy of Egyptian descent. Available literature shows that “…this result was surprising not only for its demonstration of the remarkable antiquity for which molecular genetic analysis was apparently possible, but also for the large DNA fragment sequenced” (O’Rourke et al 217).
The importance of DNA sequencing in physical anthropology cannot be overstated, mainly when it comes to analyzing mutations, which occurs in our DNA at a regular rate and is often passed along to our children without our express knowledge (Bradley 342; Jurmain et al 113; Long et al 30). Additionally, genetic sequencing makes it possible for anthropologists to analyze the differences (polymorphisms) that, on a general genotypic level, make us all exceptional and further analysis of these differences reveals how closely we are related (Ratto & Beaulieu 178). This is a major concern for physical anthropology.
More recent discoveries have demonstrated how studies in ancient DNA continue to broaden the nature and scope of our understanding in regard to the Neandertals. Indeed, “…an analysis of mitochondrial (mt) DNA extracted from multiple Neandertal fossils have confirmed abundant skeletal evidence that Neandertals were biologically distinct (i.e., formed reciprocally monophyletic groups) from living and Holocene (recent) humans and at least some more ancient modern humans” (Weaver & Roseman 677-678). This discovery, according to these authors, is unique by virtue of the fact that the uniqueness of Neandertal mtDNA comprehensively demonstrates that either contemporary human or Neandertal populations deviated deeper in the past, or human mtDNA variety was much bigger and more subdivided in the past that it is currently. This orientation has important ramifications to the field of physical anthropology.
Conclusion
Apart from demonstrating knowledge on DNA, this paper has examined how DNA has changed the field of physical anthropology, in addition to sampling some of the most important discoveries in DNA research that have a direct bearing on the field of physical anthropology. It has been revealed how the field of physical anthropology has benefitted immensely from traditional as well as recent DNA research, particularly with regard to explaining the uniqueness of humans, behavioral adaptations, evolutionary perspectives, racial issues, and sexual orientations. However, as noted in current literature, much more needs to be done to enable DNA research to successfully answer critical questions that have been bothering anthropologists throughout the years. For instance, DNA research needs to explain the issues of disease susceptibility in a much more comprehensive manner to enable humans avoid the multiplicity of maladies that have been presenting within the environment.
Works Cited
Bradley, B.J. “Reconstructing Phylogenies and phenotypes: A molecular view of human population.” Journal of Anatomy 221.4 (2008): 337-353. Web.
Broida, J. (2011). Ancient DNA in Physical Anthropology: A Review. Berlin: VDM Verlag Dr. Muller. 2011. Print
Jurmain R., Kilgore, L., Trevathen, W., & Ciochon, R.L. Introduction to Physical anthropology 2011-2012. Belmont, CA: Wadsworth, Cengage Learning, 2010. Print.
Krogman, W.M. “fifty Years of Physical Anthropology: The Men, the Material, the Concepts, the Methods.” Annual Review of Anthropology 5.1 (1976): 1-14. Web.
Long, J.C., Jie, L., & Healy, M.E. (2009). “Human DNA Sequences: More Variation and Less Race.” American Journal of Physical Anthropology 139.1 (2009): 23-34. Web.
Mark, S.J. “Genes, Bodies, and Species.” In: P.N. Peregrine, C.R. Ember, & M. Ember (Eds). Physical Anthropology: Original Readings in Methods and Practice. Upper Saddle River, NJ: Prentice Hall, 2002. Print.
McBrinn, M. “Everything is New Again: Recent Approaches to Research on the Archaic Period in the Western United States.” Journal of Archeological Research 18.3 (2010): 289-329. Web.
Muehlenbein, M.P. Human Evolutionary Biology. Cambridge: Cambridge University Press. 2010. Print.
O’Rourke, D.H., Heyes, M.G., & Carlyle, S.W. “Ancient DNA Studies in Physical Anthropology.” Annual Review of Anthropology 29.2 (2007): 217-242. Web.
Ratto, M., & Beaulieu, A. Banking on the Human Genome Project.” Canadian Review of Sociology & Anthropology 44.2 (2007): 175-200. Web.
The International History Project. Anthropology. 2001. Web.
Weaver, T.D., & Roseman, C.C. “Ancient DNA, Late Neandertal Survival, and Modern-Human Neandertal Genetic Admixture.” Current Anthropology 46.4 (2005): 677-683. Web.