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Background: After three decades of mtDNA studies on human evolution the only incontrovertible main result is the African origin of all extant modern humans. In addition, a southern coastal route has been relentlessly imposed to explain the Eurasian colonization of these African pioneers. Based on the age of macrohaplogroup L3, from which all maternal Eurasian and the majority of African lineages originated, that out-of-Africa event has been dated around 60-70 kya. On the opposite side, we have proposed a northern route through Central Asia across the Levant for that expansion. Consistent with the fossil record, we have dated it around 125 kya. To help bridge differences between the molecular and fossil record ages, in this article we assess the possibility that mtDNA macrohaplogroup L3 matured in Eurasia and returned to Africa as basic L3 lineages around 70 kya/
The oldest M and N Eurasian clades are found in southeastern Asia instead near of Africa as expected by the southern route hypothesis. The split of the Y-chromosome composite DE haplogroup is very similar to the age of mtDNA L3. A Eurasian origin and back migration to Africa has been proposed for the African Y-chromosome haplogroup E. Inside Africa, frequency distributions of maternal L3 and paternal E lineages are positively correlated. This correlation is not fully explained by geographic or ethnic affinities. It seems better to be the result of a joint and global replacement of the old autochthonous male and female African lineages by the new Eurasian incomers. Conclusions: These results are congruent with a model proposing an out-of-Africa of early anatomically modern humans around 125 kya. A return to Africa of Eurasian fully modern humans around 70 kya, and a second Eurasian global expansion by 60 kya. Climatic conditions and the presence of Neanderthals played key roles in these human movements.
originally posted by: punkinworks10
So, isnt this interesting
Background: After three decades of mtDNA studies on human evolution the only incontrovertible main result is the African origin of all extant modern humans. In addition, a southern coastal route has been relentlessly imposed to explain the Eurasian colonization of these African pioneers. Based on the age of macrohaplogroup L3, from which all maternal Eurasian and the majority of African lineages originated, that out-of-Africa event has been dated around 60-70 kya. On the opposite side, we have proposed a northern route through Central Asia across the Levant for that expansion. Consistent with the fossil record, we have dated it around 125 kya. To help bridge differences between the molecular and fossil record ages, in this article we assess the possibility that mtDNA macrohaplogroup L3 matured in Eurasia and returned to Africa as basic L3 lineages around 70 kya/
Eurasian origin of mtDNA L3 and Y-chromosome DE
A 70 Kya return to africa? Toba related migrations.
That 70 Kya window also has migrations of North American Mammoths to asia, and North American mountain lions into Eurasia to become african cheetahs.
originally posted by: Pandaram
a reply to: JohnnyCanuck
Kya means ‘what’ in hindi.
HSS is a building equipments hire company in england
FFS.. use the language!
originally posted by: punkinworks10
That 70 Kya window also has migrations of North American Mammoths to asia, and North American mountain lions into Eurasia to become african cheetahs.
originally posted by: redhorse
Your title is misleading. The proposition isn't about Eurasian origins for modern humans but about a return to Africa for the L3 mutation from Eurasia and more specifically, exactly what route was taken.
A nearly complete skull of a primitive cheetah that sprinted about in China more than 2 million years ago suggests the agile cats originated in the Old World rather than in the Americas.
The extirpation of cheetahs in North America 10,000-12,000 years ago, combined with a 100,000 year earlier migration of cheetahs out of North America across the Bering straits then down to Africa, produced a series 'populations bottlenecks' where cheetah ancestors dropped to low numbers and were obliged to inbreed, mating with close relatives to survive.
originally posted by: punkinworks10
Harte,
You need to keep up to date,
The extirpation of cheetahs in North America 10,000-12,000 years ago, combined with a 100,000 year earlier migration of cheetahs out of North America across the Bering straits then down to Africa, produced a series 'populations bottlenecks' where cheetah ancestors dropped to low numbers and were obliged to inbreed, mating with close relatives to survive.
Cheetah genetic bottle necks and american origins
In my original post i omited the greater and approximation signs before the 70kya.
I've read another paper that puts the cheetah migration greater than 75kya and less than 125, depending on the mutation rate approximation.
There is also evidence for an incursion of north american wolves into eurasia during this time window.
Im pretty certain there are also E➡W movements of other mammals at the same time.
The marked uniformity of mtDNA and a reduction in microsatellite allele size expansion indicates that North American pumas derive from a recent (late Pleistocene circa 10,000 years ago) replacement and recolonization by a small number of founders who themselves originated from a centrum of puma genetic diversity in eastern South America 200,000-300,000 years ago. The recolonization of North American pumas was coincident with a massive late Pleistocene extinction event that eliminated 80% of large vertebrates in North America and may have extirpated pumas from that continent as well.
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Conclusions: These results are congruent with a model proposing an out-of-Africa of early anatomically modern humans around 125 kya. A return to Africa of Eurasian fully modern humans around 70 kya, and a second Eurasian global expansion by 60 kya. Climatic conditions and the presence of Neanderthals played key roles in these human movements
The current ice age, the Pliocene-Quaternary glaciation, started about 2.58 million years ago during the late Pliocene, when the spread of ice sheets in the Northern Hemisphere began. Since then, the world has seen cycles of glaciation with ice sheets advancing and retreating on 40,000- and 100,000-year time scales called glacial periods, glacials or glacial advances, and interglacial periods, interglacials or glacial retreats. The earth is currently in an interglacial, and the last glacial period ended about 10,000 years ago. All that remains of the continental ice sheets are the Greenland and Antarctic ice sheets and smaller glaciers such as on Baffin Island.