Southern African ancient genomes estimate modern human divergence to 350,000 to 260,000 years ago
Carina M. Schlebusch et al.
楊茂榮 陳柏佑
When does anatomically modern humans appears?
anatomically（解剖學上的）
modern humans
When does Anatomically modern humans appears?
In archeology,
we find some early fully
modern human remains and determinate the age of the remain by Half-life
determination.
(半衰期測定)
In genetics,
we try to calculate the
distance between modern humans and estimate the deepest split time (which means their common
ancestor) by mutation rate.
The earliest
modern human remain
- Omo remains
The Oldest Fossil (化石) Remains of Anatomically Modern Humans.
It is estimated to be there about 195,000 years ago.
Was discovered between 1967 and 1974 at the Omo Kibish sites near the Omo River, Ethiopia.
Estimation by
Genetics
Intuition of
Estimation by Genetics
1. Find 2 groups of modern humans, both of them have obvious modern human features.
Intuition of
Estimation by Genetics
1. Find 2 groups of modern humans, both of them have obvious modern human features.
2. Estimate the age of their common ancestor, the ancestor must have modern human features already.
150000 years Now
Intuition of
Estimation by Genetics
1. Find 2 groups of modern humans, both of them have obvious modern human features.
2. Estimate the age of their common ancestor, the ancestor must have modern human features already.
3. The farther distance between two picked groups, the better.
280000 years
Now
Khoe-San
Genetic studies identified modern southern African Khoe-San populations as carrying more unique
variants and more
divergent lineages than other living groups.
Khoe-San
Genetic studies identified modern southern African Khoe-San populations as carrying more unique
variants and more
divergent lineages than other living groups.
PCA of ancient southern Africans and a global comparative data set.
Modern Bantu-language-speaking group
They origin from Nigeria and Cameroon, and start to migrate at around 3000 years ago.
They reach South Africa at around 1700 years ago.
Modern Bantu-language-speaking group
Nowadays, They
distributed across Central Africa and South Africa.
Their gene is very different from
Khoe-Sans.
Middle Stone Age sites in KwaZulu-Natal, South Africa
The author studied:
3 stone age hunters / gatherers, about 2000 years old.
4 iron age farmers, about 300~500 years old.
Middle Stone Age sites in KwaZulu-Natal, South Africa
Modern Khoe-San
Modern Bantu- language-speaking groups
Middle Stone Age sites in KwaZulu-Natal, South Africa
Modern Khoe-San
Modern Bantu- language-speaking groups
Consistent with the archeology evidence that
Bantu-language-speaking groups moved to South-East Africa around 1700 years ago.
Middle Stone Age sites in KwaZulu-Natal, South Africa
Modren Khoe-San
Modern Bantu- language-speaking groups
Bantu-language-speaking groups and Iron age farmers not only have similar gene, but also have similar distance to Khoe-San
Admixture of Modern Khoe-San
Also by Genetics,
Modern Khoe-San are now know to be mixed with Ju|’hoansi / Nama at around 1500 / 1300 years ago. These people are hordes (遊牧民族) distributed in South Africa.
The admixture would disarrange the estimation of common ancestors.
wiki: Juǀ'hoan dialect
Middle Stone Age sites in KwaZulu-Natal, South Africa
Modern Khoe-San
Modern Bantu- language-speaking groups
Ｘ
Ballito Bay A’s gene
High-quality Genome Sequencing
1. Using B. Bay A Boy &
Bantu.
2. Assuming 1.25 *
10^-8 mutations per generation.
-> The deepest split time: 285~356ka.
1. Using B. Bay A Boy &
Bantu.
2. Assuming 1.25 *
10^-8 mutations per generation.
Two plus Two(TT) method
Brief Summary (So far)
1. B. Bay A v.s. Dinka
demonstrating the deepest split at >260 ka.
2. Ju|’hoansi v.s. Dinka 258~255 ka.
-> deepest split among modern humans occurred at between 350 and 260 ka
Consistent; with the opening of Middle Stone Age
Conclusion
Archaeological, fossil, and genetic records increasingly point toward a modern human development that includes southern Africa.
