Key Knowledge:
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Modern human populations can be traced to explain the emergence of human haplogroups (i.e. different ethnicities) around the world
- Populations can be traced using fossil and DNA evidence (either mtDNA or whole genomes)
Haplogroups
Fossil evidence can be used to show the occurrence of a species within a particular region, however populations that are closely related (but distinct) may be difficult to distinguish based on fossilised remains (due to insufficient differences in their biological structure)
- Differentiating between different populations of modern humans will therefore generally require the use of DNA evidence
DNA evidence may be able to be collected from fossils depending on how they have been preserved
- Typically, DNA evidence is difficult to collect from fossils that are older than ~60,000 years due to the degradation of the DNA sequence
Mitochondrial DNA provides an accurate way of comparing closely related populations (due to no recombination and a high copy number)
- mtDNA can also be used to estimate times of evolutionary divergence due to a stable rate of mutation (i.e. it is a molecular clock)
Analysis of the whol genome (nuclear DNA) can also be useful because it can be used to demonstrate interbreeding between populations, as sexual reproduction facilitates the recombination of genetic information from both populations
- For example, European and Asian populations share ~4% of their DNA with Neanderthals, while Polynesians carry ~5% Denisovan DNA
A genetic population group who share a common ancestor (on either the paternal or maternal line) is called a haplogroup
- Paternal haplogroups are determined by Y chromosome analysis, while maternal haplogroups are determined from mtDNA
Human Migration
Fossil evidence shows that early hominin species originated in Africa (the ‘cradle of civilisation’) and then distributed around the world
- However, there was considerable debate regarding the specific evolutionary pathway of modern human populations (Homo sapiens)
Two competing theories have been proposed by anthropologists:
- According to the ‘Out of Africa’ model, modern humans evolved in Africa before migrating around the globe
- According to the ‘Multiregional’ model, modern humans evolved as one interconnected global population after early hominin migration
Recent mtDNA evidence supports the 'Out of Africa' model, with modern humans replacing existing hominin species in Europe and Asia
- However debate still exists as to whether the global expansion of modern humans occurred as a single exodus or via several migrations
⇒ Click on the diagram to compare the migration map with a phylogeny tree
First Nations
From the mtDNA evidence, it is currently believed that ancestral Aboriginal and Torres Strait Islander populations migrated to Australia approximately 50-60,000 years ago, explaining the strong connection Indigenous populations have to Country and Place
- For many Indigenous people, land relates to all aspects of existence – including culture, spirituality, law, family and identity
- Rather than owning land, each person belongs to the land via a shared kinship (the land sustains the people, the people sustain the land)
- To First Nations people, Country is alive with a collective agency (hence the capitalisation – Country is not an ‘it’, but a ‘who’)
Further colonisation of Australia only occurred in the late 19th century with European settlement via the First Fleet
- Because of the kinship shared with the land, the dislocation of Indigenous Australians impacted their very identity and sense of culture