The Australian Aboriginal People: Dating the Colonization of Australia :: Biology Biological Colony Essays

The Australian Aboriginal People: Dating the Colonization of Australia Abstract The colonization of each continent by modern human populations remains an important question in our history as a species. Studies of variations in mitochondrial genomes, Y-chromosomes, satellite DNA, and other genetic markers can be used to estimate the time of divergence of one population from another. Recent advancements in technology have advanced our capabilities in genetic analysis. In particular, PCR can be used to amplify, study, and sequence DNA from long-deceased specimens. Ingman and Gyllensten studied 101 complete mitochondrial genomes from contemporary populations in Australia and many other regions. The mitochondrial genetic diversity of Aboriginals is remarkably high, similar to that found in Asia. Ingman and Gyllesten estimated colonization of Australia at 40,000-70,000 years ago and supported multiple waves of migration. Another study by Adcock and others indicates that anatomically modern humans were present in Australia before complete fixation of the mtDNA lineage, but does not establish a colonization date. A study of Y-chromosome variation by Vandenburg and others in 1999 revealed two haplotypes unique to Australian Aboriginals. Most (78%) of Aboriginal haplotypes fell into two clusters, possibly indicating two original, separate lineages of founding Aboriginal Australians. As recently as the 1960’s, anthropologists predicted the colonization of Australia at less than 10,000 years ago. Advancments in thermoluminescence dating pushed back the estimated colonization time to 50,000-60,000 years ago in the early 1990’s. Improvements in thermoluminescence and carbon dating techniques adjusted previous colonization dates of 50,000-60,000 years to approximately 45,000 years. The results of morphological dating best-support the multiregional evolution hypothesis of modern humans, and further complicate the possible ancestry of modern Australian Aboriginals. Mitochondrial DNA analysis, recent thermoluminescence dates, and the history of ocean levels coincide roughly to indicate a colonization of Australia at approximately 50,000 years ago. Introduction Throughout recorded history, humans have been defined by a desire to know ourselves: Where did we come from? How did we get here? Where are we going? Many questions are directed towards our appearance as a species and subsequent populating of the earth, -- piece by piece. One particularly large piece of the earth is Australia: a continent, a country, and a mystery in human history. Though the major events in Australian natural history have been revealed, for the most part, human history remains a great topic of debate.