Australia: The Land Where Time Began

A biography of the Australian continent 

Australian Colonisation – the Genetic Evidence

Mitochondria are inherited by every person only from their mother and mitochondrial DNA (mtDNA) which has a high mutation rate, is abundant in many cells, and provides a relatively simple way to study the recent evolutionary history of human lineage. Geneticists have found that all humans are descended from a common mtDNA ancestor; the distance from the common ancestor of any population such as Australian Indigenes can be calculated (Relethford, 2001; Forster, 2004).  It is also possible to estimate the length of time that has passed since that ancestor when a constant mutation rate is assumed (Ingman et al., 2000). The most recent common female ancestor of Aboriginal people is suggested by analyses of this kind to have lived at about 74,000 BP (Ingman & Gyllensten, 2003; Merriwether et al., 2005; van Holst Pellekaan & Harding, 2006). Other studies indicate that there were rapid, more recent dispersals of anatomically modern humans at 65,000-60,000 BP through South Asia towards Australia (Macaulay et al., 2005; van Holst Pellekaan et al., 2006), and at 66,000-42,000 years ago a dispersal towards New Guinea (Forster et al., 2001). These time estimate often have an uncertainty of 20% or more, with all pointing towards the common ancestor living between 90,000 and 50,000 years ago.  Also, it is not known where this woman lived; it may have been outside Australia, therefore the colonisation of Australia is not dated by mtDNA estimates. Any association with the Toba eruption and migration towards Australia is not well defined.

Sources & Further reading

1. Hiscock, Peter, 2008, Archaeology of Ancient Australia, Taylor & Francis.