Molecular archaeology is an emergent field in archaeology that has been brought about by the advancements of the recognition and understanding of DNA. This new developing branch of archaeology focuses on the acquisition of either DNA or mtDNA (mitochondrial DNA) and being able to determine species of natural archaeological finds as well as determine blood lines and/or sex of animal or human remains. These DNA "residues can be used to reconstruct subsistence and related cultural activities with an accuracy not possible using standard archaeological methods" (Loy). As our technology advances as well as our knowledge of the DNA itself our understanding of ancient peoples, plants, and animals, will allow us a biological window into their lives.
Genetic source material may be drawn from a number of areas depending on the state of the organism being studied and what kind of organism it is. It can be taken from biological remains, skeletal remains, body tissues, hair, teeth, and in some cases fossils. A very small amount of a sample from the organism is needed to test for DNA, however there will always be a slight destruction of the specimen. As an example, "usually small amount of source material (a tooth or one to two grams of bone) are enough to perform a DNA-extraction" (Jan). The DNA quality or even it’s existence is dependent on the environment in which the organism died and has been decaying. The factors that could effect the DNA "include chemical intrusion into the specimen and physical, geological, ecological, and biological circumstances of the individuals history" (Jan). Very cold temperatures as well as arid climates are the best preservatives of DNA, the more humid or damp, the more decay that will occur and the more chance there is for contamination of the specimen. Examples of well preserved specimens for DNA extraction are those of the "Tyrolean Ice-Man" found in the Alps and the mummies of Egypt found well preserved in the arid climate of Egyptian desert.
The method by which the DNA is collected is basically a surgical method. First, during sample collection everything should be sampled right away at the excavation site and all precautions should be taken to ensure that the sample is not infected with any other DNA so the "workers should be wearing gloves and masks and the tools used should be sterilized" (Jan). The second step is the DNA extraction from the sample and this can be done in a couple of ways, either through UV radiation or through a chemical process that will break down the sample and allow the DNA to remain afterwards. Next, the DNA must be isolated from any remaining materials so it may be studied independently. Finally, the DNA is amplified so that is can be more easily studied and produce a sample that can be compared to existing DNA sequences to determine it’s speciation.
Molecular archaeology can in time, as our knowledge and technology increases, provide us with the ability to learn more about the life of ancient individuals. It can be seen how modern humans may differ from our ancestors or what plants and animals may have existed at the time and been utilized by them, which can be found by exploring what their tools and clothing or other artifacts were constructed out of. Not every area of the world is accessible to this technology due to the variety of climates, but in those areas where suitable DNA samples may be taken a whole new knowledge of the ancient culture under examination may be gained.
(Jan):
http://www.comic.sbg.ac.at/staff/jan/ancient/About%20adna%20english.htm
(Loy):
Former link http://www.cmcb.uq.edu.au/PROJECTS/GROUPS/thl.html (2008)