First Homosapiens left Africa less than 95,000 Years ago

Squeaky the Squirrel

Some time in humanity’s past, a small group of Homo sapiens migrated out of Africa before spreading out to every possible corner of the Earth. All the women of that group carried DNA inherited from just one woman, commonly known as mitochondrial Eve, whose DNA was inherited by all humans alive today. But the exact timing of this migration is not clear, and it has sparked debate among geneticists. Now, new research published in Current Biology may help calm both sides.

Background

Recent analyses of de novo DNA mutations in modern humans have suggested a nuclear substitution rate that is approximately half that of previous estimates based on fossil calibration. This result has led to suggestions that major events in human evolution occurred far earlier than previously thought.

Results

Here, we use mitochondrial genome sequences from ten securely dated ancient modern humans spanning 40,000 years as calibration points for the mitochondrial clock, thus yielding a direct estimate of the mitochondrial substitution rate. Our clock yields mitochondrial divergence times that are in agreement with earlier estimates based on calibration points derived from either fossils or archaeological material. In particular, our results imply a separation of non-Africans from the most closely related sub-Saharan African mitochondrial DNAs (haplogroup L3) that occurred less than 62–95 kya.

http://arstechnica.com/science/2013/03/fossil-dna-used-to-reset-humanitys-clock/

http://www.cell.com/current-biology/retrieve/pii/S0960982213002157

Yitzhak Rabin

I don't understand a lot of the genetics or the genteic clock research, so excuse me if I'm speaking heresy here,

But in my mind the way scientists describe humans as having left Africa in one big migration doesn't make sense. I presume there was far more back and forth, with waves coming and going to and from Africa? Wouldn't it therefore be very hard to pin down an exact group that became us that left Africa at a specific time?

Wibbs

I'm with YR on this myself. It's unlikely it was just one group at one time. What they're actually measuring are the gene markers of the group that survived down to today. Go back say 28,000 years ago and you'd have other gene markers that no longer around. Indeed IIRC Mungo Man fro Australia has just these non surviving gene markers. His male lineage died out. And given the lad and his gang were in Australia(40Kya?) they defo got out of Africa. I'd put money there were other female lines too, but they didn't survive down to us today. Again the Anglo Saxon example in the UK. Most certainly there were AS ladies who came with the men into the new territory(for them), today no female AS line has been found to have survived down to today. That's over a thousand years, over 50, or 80 thousand years? You can bet your life there were others.

Adam Khor

I know this doesn´t have much to do with the OP, but I thought it was interesting AND it has to do with the human or pre-human radiation as well...
There is some scant but important evidence of the presence of either very early H. sapiens or perhaps even Homo erectus from the New World:

http://www.mombu.com/culture/mexico/t-did-homo-erectus-reach-america-8312177.html

Seeing as you say H. erectus reached Australia, what would you think about them reaching the Americas as well?

Wibbs

Erectus didn't get as far as Australia as far as I know. Kinda surprising actually, given a possibly more primitive human made it to Flores and Erectus made it as far north as Scotland and right over to the Java too. Maybe there was just too much of a water gulf between Asia and Australia at the time when they were on the move. Or maybe they just haven't been found yet. Australia is biiiig so it's possible.

The Americas are a much harder sell for me. Without the ability to make tailored clothing the ice bridge would have been just too much of a barrier for pre modern humans and in the warmer periods the ocean distance would have been just too far. Of the evidence for earlier humans Ive heard of some south American anomalies alright, but haven't seen decent literature/pics on them. However I do believe modern humans were there before the "Clovis" culture(11Kya IIRC) that is a line treated as if written in stone by US researchers. I'd not be shocked to find out modern humans made it say 18-20Kya. My jaw would drop through the floor to hear pre modern humans made it though.

Adam Khor

Wibbs wrote: »

Erectus didn't get as far as Australia as far as I know.

My jaw would drop through the floor to hear pre modern humans made it though.

Oh, my mistake then.