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What is a haplotype
A region of DNA in the D-loop of mitochondrial DNA (mtDNA) that varies between individuals
What is a haplogroup
A group of people with similar haplotypes who share a common ancestor
What is the 'Out of Africa' theory
The theory that modern humans (Homo sapiens) evolved in Africa and then migrated to all parts of the Earth over hundreds of thousands of years
How has the 'Out of Africa' theory been challenged
The discovery of new fossils and the use of molecular dating techniques have contested this theory, leading to debates about the migration patterns of modern humans
What does the traditional 'Out of Africa' hypothesis propose about the migration of Homo sapiens
It suggests that all Homo sapiens evolved in Africa and began migrating out through North Africa about 60,000 years ago
What does the 'Out of Africa II' hypothesis propose about the migration of Homo sapiens
It proposes two waves of migration:
a small-scale migration about 120,000 years ago to regions in the Middle East (modern Israel, Jordan, Lebanon, Syria, and Iraq)
a large-scale migration about 60,000 years ago to Europe, Asia, and beyond
How is the 'Out of Africa II' hypothesis different from the traditional 'Out of Africa' theory
The 'Out of Africa II' hypothesis includes an additional earlier migration wave (120,000 years ago) and suggests a two-phase migration process
the traditional theory primarily focuses on a single migration event around 60,000 years ago
What are the oldest fossils attributed to Homo sapiens found outside Africa, and where were they discovered
Misliya Cave: Upper jawbone, dated to ~180,000 years old.
Qafzeh Cave: Remains of five individuals, dated to ~120,000 years old.
Skhul Cave: Remains of seven adults and three children, dated to ~90,000 years old.
What do the fossils found in Israel suggest about the migration of Homo sapiens
They provide evidence that modern humans left Africa earlier than the previously suggested 60,000 years ago
How has the movement of modern humans been tracked
Through fossils and DNA evidence, showing migration from North Africa into Europe and Asia, then into the Indian subcontinent, Oceania, and eventually to the American continent during the Pleistocene ice age via a land bridge connecting Asia and Alaska
When and where did humans colonize the last places on Earth
Micronesia and New Zealand, which were colonized around 2,500 years ago
Examples of evidence of migration
location of discovery
fossil evidence
age of fossil/s
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What is a key characteristic of mitochondrial DNA (mtDNA) in terms of inheritance
mtDNA is inherited only from the maternal lineage, so no recombination occurs
Why does mtDNA have a higher mutation rate compared to whole genome DNA
mtDNA has a higher mutation rate because it lacks repair mechanisms
How many genes and nucleotide pairs does mitochondrial DNA contain
Mitochondrial DNA contains 37 genes and 16,569 nucleotide pair
What is one limitation of using mtDNA for genetic studies
mtDNA does not provide evidence of interbreeding and does not show the whole population's genetic history
How does whole genome DNA differ from mtDNA in terms of inheritance
Whole genome DNA includes both maternal and paternal lineages due to recombination
How many genes and nucleotide pairs are in whole genome DNA
Whole genome DNA includes over 20,000 genes and 3.2 billion nucleotide pairs
Why does whole genome DNA have a lower mutation rate compared to mtDNA
Whole genome DNA has a lower mutation rate because it has repair mechanisms
What advantage does whole genome DNA have over mtDNA in terms of evidence
Whole genome DNA provides evidence of interbreeding with other species
How is mitochondrial DNA (mtDNA) inherited
mtDNA is inherited only from the maternal lineage; only mothers pass mtDNA to their children
What is the non-coding region in mitochondrial DNA known as, and what are its components
The non-coding region in mtDNA is known as the D-loop, which includes two hypervariable regions: HVR1 and HVR2
Why does the D-loop region of mtDNA have a higher mutation rate
The D-loop has a higher mutation rate due to its lack of repair mechanisms and its high level of mutation in the hypervariable regions
What is a haplotype in the context of mtDNA
A haplotype is the mtDNA sequence of the D-loop unique to each individual
What are haplogroups, and how are they classified
Haplogroups are clusters of similar haplotypes and are classified using capital letters (e.g., H, T, U)
How are haplogroups useful in studying human migration
the lack of genetic recombination
the high mutation rate in the D-loop
How has new mtDNA research dated the habitation of Aboriginal peoples in Australia
New studies have dated Aboriginal habitation to approximately 50,000 years ago
What is the proposed migration route of the ancestors of Aboriginal peoples
The proposed migration route is from north-east Africa through the Middle East and Asia, then south to the landmass of Sahul
What do some mtDNA haplogroups unique to Aboriginal peoples indicate
Unique haplogroups reflect the long time frame since Aboriginal peoples diverged from other groups and provide evidence of their long-term presence in Australia
What does the large variation in mtDNA haplogroups among Aboriginal peoples suggest
The large variation indicates a significant period of isolation and divergence from other populations, supporting the long duration of Aboriginal habitation in Australia
